© 2018 Vishal Singh Chundawat -...

COMPARISON OF EMBODIED ENERGY OF STUDENT HOUSING IN THE UNITED STATES AND INDIA- A CASE STUDY

By

VISHAL SINGH CHUNDAWAT

A THESIS PRESENTED TO THE GRADUATE SCHOOL

OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF

MASTER OF SCIENCE IN CONSTRUCTION MANAGEMENT

UNIVERSITY OF FLORIDA

2018

© 2018 Vishal Singh Chundawat

To my Grandparents, my mother Mrs. Neelam Chundawat, father Mr. Pratap Singh Chundawat, younger brother Sangram Singh Chundawat and all the well-wishers who

were there for me when I needed them The positivity and confidence from my family and friends inspires me to keep going on

the righteous path.

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ACKNOWLEDGMENTS

Firstly, I would like to express my sincere gratitude to my advisor Dr. Ravi

Srinivasan for continuous support and motivation during this research period. He guided

me every step and made me realize the importance of this study. It was an amazing

journey under his guidance and it developed a research acumen in me.

I would like to acknowledge the guidance and support given by my committee

members Dr. Robert Ries and Dr. Abdol Chini. I am grateful to them for their valuable

comments and inputs. I would also like to give a special thanks to Mr. Dustin Stephany,

Sustainability coordinator at the University of Florida who provided valuable inputs and

ensured the data availability for the research. I am also grateful to Dr. E. Rajasekar and

Mr. Anil from Indian Institute of Technology, Roorkee for helping me with the data

acquisition and assisting me during this study.

My special thanks to my friends Kalieshwar Srinivasan and Martin Nwodo for

their time and inputs in this work. Finally, I would like to thank all my friends for being a

good support and assisting me in whenever needed.

JAI EKLINGJI, JAI MEWAR!!

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TABLE OF CONTENTS

page

ACKNOWLEDGMENTS .................................................................................................. 4

LIST OF TABLES ............................................................................................................ 7

LIST OF FIGURES .......................................................................................................... 8

LIST OF ABBREVIATIONS ........................................................................................... 10

ABSTRACT ................................................................................................................... 11

CHAPTER

1 INTRODUCTION .................................................................................................... 12

Construction Materials in the U.S and India ............................................................ 13 Thesis Objectives ................................................................................................... 14

2 LITERATURE REVIEW .......................................................................................... 16

Life Cycle Assessment............................................................................................ 16 Applications of LCA ................................................................................................ 17

LCA Tools ............................................................................................................... 18

LCA Comparison of Different Materials................................................................... 20

Example Studies Using LCA ................................................................................... 23 BIM and LCA .......................................................................................................... 23

Significance of Embodied Energy ........................................................................... 25 Components of Embodied Energy .......................................................................... 26 Embodied Energy of Reinforced Concrete .............................................................. 27

Parameters for Embodied Energy Measurement .................................................... 28 Research Tools Used to Calculate Embodied Energy ............................................ 28

EIO-LCA ........................................................................................................... 28

Athena Impact Estimator .................................................................................. 31 SEER................................................................................................................ 32

3 METHODOLOGY ................................................................................................... 34

Case Study Buildings .............................................................................................. 35 United States – Cypress Hall ............................................................................ 35 India – Transit Housing .................................................................................... 37

Scope and Limitation .............................................................................................. 40

Quantity Takeoffs .................................................................................................... 42 Cypress Hall ..................................................................................................... 42 Transit Housing ................................................................................................ 42

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Calculation of Index Factor: .............................................................................. 44

Cost Estimation Using RS Means .................................................................... 44

Embodied Energy Calculations ............................................................................... 45 Cypress Hall (Using EIO LCA) ......................................................................... 45 Cypress Hall (Using Athena Impact Estimator) ................................................ 46 Transit Housing ................................................................................................ 47

4 RESULTS AND DISCUSSION ............................................................................... 49

Embodied Energy Comparison ............................................................................... 49 Embodied Energy Analysis for Cypress Hall Using EIO-LCA ........................... 49 Embodied Energy Analysis for Cypress Hall Using Athena Impact Estimator .. 50 Embodied Energy of Transit Housing Using SEER .......................................... 50 Observations .................................................................................................... 51

Comparing EE of Interior Wall material ............................................................ 56 Recommendations ........................................................................................... 58

5 CONCLUSION ........................................................................................................ 59

APPENDIX

A CYPRESS HALL 3D PERSPECTIVES ................................................................... 61

B ATHENA RESULTS AND COST INDEX ................................................................ 64

LIST OF REFERENCES ............................................................................................... 66

BIOGRAPHICAL SKETCH ............................................................................................ 69

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LIST OF TABLES

Table page 3-1 Comparison of the different construction assemblies used in the two

buildings ............................................................................................................. 40

3-2 Quantity take-off table for Cypress Hall .............................................................. 43

3-3 Material quantity takeoff from the available BOQ for Transit Housing ................ 44

3-4 Cost estimates .................................................................................................... 45

3-5 Embodied energy of construction material of $1Million ...................................... 46

3-6 Total embodied energy calculation for Cypress Hall using EIO-LCA .................. 47

3-7 Embodied energy calculations for Cypress Hall from Athena Impact Estimator ............................................................................................................ 48

3-8 Total embodied energy calculation for Transit Housing ...................................... 48

4-1 Embodied energy of envelope ............................................................................ 55

8

LIST OF FIGURES

Figure page 2-1 Schematic presentation of environmental mechanisms underlying the

modeling of impacts and damages in Life Cycle Assessment (ISO 14044: 2006). Source: (Buyle et al., 2013) ..................................................................... 18

2-2 System boundaries to evaluate the impacts on the built environment. Source: (Srinivasan et al., 2014) ...................................................................................... 20

2-3 Cumulative energy consumption with different wall materials over a life of 50 years. Source: (Huberman & Pearlmutter, 2008)................................................ 21

2-4 Prospective framework for integrating LCA features into a BIM tool. Source: (Asadi et al., 2017) ............................................................................................. 25

2-5 The energy involved in the production of steel worth $1million .......................... 31

3-1 Methodology flow chart ....................................................................................... 34

3-2 First floor Revit model section of Cypress Hall ................................................... 36

3-3 Structural image of Cypress Hall from the Revit model ...................................... 36

3-4 East elevation of Cypress Hall ............................................................................ 37

3-5 Key Plan of the Transit Housing ......................................................................... 38

3-6 North Elevation of Transit Housing building ........................................................ 38

3-7 East Elevation of Transit Housing building ......................................................... 39

3-8 Level 1 Floor Plan for Building B1 (Transit Housing) .......................................... 39

3-9 Creating quantity take-off schedule using Revit.................................................. 43

4-1 Embodied energy share for different materials used in Cypress Hall from EIO-LCA ............................................................................................................. 49

4-2 Embodied energy share for different elements used in Cypress Hall from Athena Impact Estimator .................................................................................... 50

4-3 Embodied energy share for different materials used in Transit Housing using SEER .................................................................................................................. 51

4-4 Embodied energy (MJ/sf) for Cypress Hall and Transit Housing ........................ 52

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4-5 Comparison of EE contribution of reinforced steel and concrete in both the buildings ............................................................................................................. 52

4-6 Comparing concrete used in the buildings per unit area ..................................... 53

4-7 Comparing steel reinforcement used in the buildings per unit area .................... 53

4-8 Comparison of EE values of steel and concrete ................................................. 54

4-9 Embodied energy comparison of exterior envelope ............................................ 55

4-10 Embodied energy comparison of interior walls of both buildings ........................ 56

4-11 Embodied energy comparison of Cypress Hall between EIO-LCA and Athena Impact Estimator ................................................................................................. 57

4-12 Comparison of EE values derived from EIO-LCA and Athena Impact Estimator for different assemblies of Cypress hall .............................................. 58

A-1 SE Perspective ................................................................................................... 61

A-2 NW Perspective .................................................................................................. 61

A-3 SW Perspective .................................................................................................. 62

A-4 NW Perspective .................................................................................................. 62

A-5 Roof Section for Cypress Hall............................................................................. 63

B-1 ATHENA Impact Estimator Report ..................................................................... 64

B-2 RSMeans Cost Index .......................................................................................... 65

10

LIST OF ABBREVIATIONS

AAC

CMU

EE

GGBS

GHG

IIT

IPP

LCA

NAICS

SEER

SETAC

Autoclaved Aerated Blocks

Concrete Masonry Unit

Embodied Energy

Ground Granulated Blast Furnace Slag

Greenhouse Gas

Indian Institute of Technology

Integrated Product Policy

Life Cycle Assessment

North American Industry Classification System

Schedule of Embodied Energy Rate

Society for Environmental Toxicology and Chemistry

SSB

UF

Stabilized Soil Block

University of Florida

https://www.census.gov/eos/www/naics/

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Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the

Requirements for the Degree of Master of Science in Construction Management

COMPARISON OF EMBODIED ENERGY OF STUDENT HOUSING IN THE UNITED STATES AND INDIA- A CASE STUDY

By

Vishal Singh Chundawat

May 2018

Chair: Ravi S. Srinivasan Co-chair: Robert J. Ries Major: Construction Management

Embodied energy is the energy required in the manufacturing process of a

product. It involves the energy used in raw material extraction, transportation of raw

material from extraction site to the manufacturing location, and processing of raw

materials to produce the final product. In the U.S., buildings account for more than 40

percent of carbon emissions. This carbon emission is associated with the transportation

energy of building products from manufacturer to construction site, embodied energy of

products, and operational energy use of the building during its useful life. With global

warming and fuel crisis becoming a major issue across the globe, it becomes essential

to understand the carbon emissions and fuel consumption associated with building

construction to develop mitigation efforts. Needless to say, the construction means, and

methods varies by countries and their impact to the environment varies accordingly.

This study aims to draw a comparison between the embodied energy of a residential

building in the U.S and India. For the purposes of this study, the functional use of the

building selected in the U.S. and India were maintained similar. The study concludes

with recommendations for reduced embodied energy.

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CHAPTER 1 INTRODUCTION

According to the United Nations Environment Programme (UNEP), three planets

the size of the earth will be required by 2050 to address the growing demands of the

population. This unprecedented growth along with climate change has put undue

pressure on available resources and simultaneously polluted the environment. As a

result, research in all fields that demand massive amounts of energy has increased.

While the U.S. is the largest economy in the world, India is one of the fastest growing

economies. Both countries are witnessing a boom in the construction industry. In 2010,

the U.S. construction industry accounted for $611 billion of expenditures, which is 4.4%

of the GDP and more than any other industry. Construction activities account for the

highest environmental impact, land use, solid waste generation, health hazards, and

global climate change. The construction sector constitutes roughly 40% of energy

demand in all countries around the world (Antón & Díaz,2014). The primary energy

utilization in buildings is in the following: (1) the embodied energy owing to the

production of the building materials; (2) transportation energy, which is the energy spent

in fuel for transporting the material from the manufacturer to the construction site; and

(3) the operational energy for day-to-day operation of the building during its useful

lifetime.

In the U.S., construction and renovation activities account for 80% of all

resources by mass, 30% of raw materials, and 25% of water. The waste produced from

construction projects annually is 164,000 million tons, which accounts for 30% of the

landfill waste (Kucukvar & Tatari, 2013).

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In India, annual consumption of construction material exceeds two billion tons

every year. Production and transport of raw materials lead to greenhouse gas emissions

(GHG), pollution, and environmental imbalances. Approximately 30% of GHG emissions

are due to the construction sector. The embodied energy is between 3.72 MJ/Kg and

2.38 MJ/kg for cement, 32.24 MJ/Kg for steel, 141.55 MJ/Kg for aluminum cold rolled

coils, and 2.42 MJ/Kg for bricks used in India (Praseeda, Reddy, & Mani, 2015). These

high energy data reflect the cruciality of understanding energy associated with

construction and the importance of research and development in this field.

Construction Materials in the U.S and India

In the last few decades, the world has witnessed a tremendous change in global

collaborations in the construction industry. Currently, construction involves a team of

architects, engineers, contractors, labors, and suppliers from different nations coming

together for the projects. This diversity brings knowledge transfer and technology

sharing among the countries. Construction in the U.S. involves heavy usage of wood

along with concrete foundations. Steel is another major building material used in the

U.S. since the industrial revolution. It is mainly used in skyscrapers as it is lighter, more

flexible, and easier to construct than concrete. Whereas, in India, a mix of brick

masonry, cement, and steel is the main construction material for the vast majority of

construction. Masonry construction is labor intensive and takes much longer than wood

and steel structures. The masonry blocks used are manufactured locally which reduces

the transportation energy.

Nevertheless, building materials are associated with high embodied energy

which in turn have a significant impact on the environment. Embodied energy is the

energy required in the manufacturing process of a product. It involves the energy used

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in raw material extraction, transportation of raw material from extraction site to the

manufacturing location, and processing of raw materials to produce the final product.

Using Life Cycle Assessment (LCA), one can assess the environmental impacts and

resource utilization of building materials over their entire life. It has become an integral

part of the research in the construction industry. It can systematically and objectively

evaluate and quantify the ecological impacts. Since the beginning of the 21st century,

LCA has been a subject of research worldwide. The European Commission has

introduced its Integrated Product Policy (IPP) in this context. Other initiatives such as

UNEP and the Society for Environmental Toxicology and Chemistry (SETAC) enable

research scholars to collaborate in the knowledge gains and put them effectively into

practice (Dossche, Boel, & De Corte, 2017).

Thesis Objectives

Although there are existing studies related to embodied energy for building

materials, there is a lack of direct comparison of embodied energy analysis of buildings

in the U.S. and India. Besides, changes in construction materials used in these two

countries, the energy used for manufacturing and transportation also varies. This study

discusses the differences in embodied energy of building materials used in the U.S and

India, particularly for student housing buildings.

The thesis objectives are:

1. Evaluate the embodied energy of a student housing building in the U.S. and India.

2. Recommend alternative materials to lower embodied energy.

For embodied energy estimation, two case study buildings are used. There are two

same purpose student housing buildings located in educational institutions in the two

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countries namely, the University of Florida (UF), Gainesville, and other at the Indian

Institute of Technology (IIT), Roorkee. For embodied energy, a detailed estimation of

the quantity of material used in the buildings including structural elements, drywall, and

façade is performed.

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CHAPTER 2 LITERATURE REVIEW

This chapter discusses the various aspects of construction and the way it

impacts environment. This chapter discusses procedure followed and the tools used in

LCA studies. It follows with understanding the significance of embodied energy in

construction and the tools used in this research. It is important to realize that embodied

energy is an integral part of LCA studies.

Life Cycle Assessment

Carbon emissions, global warming, and climate change are the most commonly

discussed topics at the international level. In the last 200 years, human development

activities have increased damage to the ecosystem, and climate change is considered a

global threat today. Research has been promoted in different fields to reduce energy

consumption. Construction is considered a major consumer of energy. Studies suggest

that buildings consume up to 40% of energy and account for 36% of carbon emissions

in the European Union countries (Pikas, Thalfeldt, & Kurnitski, 2014). To reduce carbon

emissions and energy consumption, studies have been conducted around the world,

and life cycle assessment (LCA) is considered a perfect solution to analyze the impacts

of a building, from its construction stage to demolition, on the environment. LCA is

based on the international standards of series ISO 14040 and has four analytical steps:

defining the goal, creating inventory, analyzing the impact and interpreting the results.

LCA for buildings mostly involves studying embodied energy, operational energy and

transportation energy (Ortiz, Castells, & Sonnemann, 2009).

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Applications of LCA

LCA has been a useful tool for companies to make important decisions about

optimizing the environmental impacts of their products and setting the benchmark for

sustainable consumption and production. Life cycle impact assessment is the third

phase of LCA and involves converting the impacts from emissions in common units for

easy comparison for, e.g., CO2, and CH4 emissions can be expressed as CO2

equivalent emissions. LCA studies have been instrumental in energy policymaking. It

also gives the impression of environmental impacts before any investment is made in

infrastructure and energy. LCA studies are expected to gain momentum with a

collaboration between ecological sciences and economic and social dimensions of

sustainability with an aim to develop a sustainable development approach (Hellweg &

Canals, 2014).

(Buyle, Braet, & Audenaert, 2013) stated that the first mention of LCA was in the

early 1980s with research focused on the use of renewable resources. The techniques

used for LCA lacked scientific and analytic discussion. It was only in the 1990s that LCA

moved towards standardization with the publication of several scientific papers, and the

ISO 14040 standard series was published in 1997. The standardization gave a general

methodology for comparing different LCAs. It is important to understand that LCA

results are not absolute values and have no relation to the sustainability of a product,

but they play a crucial part in making comparisons of the environmental impacts of the

products. Figure 2-1 shows different methods that can be chosen to analyze the

impacts depending on the nature of research per ISO 14044.

The energy involved in the transportation of materials is generally neglected in LCA

studies because most of the raw material used is locally produced and travel distance

18

remains less. It is only when the material is procured from overseas that the

environmental impact of transportation becomes reasonable and can even reach seven

percent of the total environmental burden (Buyle, Braet, & Audenaert, 2013).

Figure 2-1. Schematic presentation of environmental mechanisms underlying the

modeling of impacts and damages in Life Cycle Assessment (ISO 14044: 2006). Source:(Buyle et al., 2013)

LCA Tools

LCA techniques have been developed to manufacture low-environmental-impact

products. Buildings are complex mixes of various materials with a long life during which

they undergo multiple changes. It makes LCA for buildings a convoluted process. There

are numerous assessment applications available to conduct detailed LCA analyses.

(Zabalza Bribián, Aranda Usón, & Scarpellini, 2009) Mentioned a software system

known as CALENER used for providing energy ratings along with energy load for

heating and cooling, energy consumption, and carbon dioxide emissions for heating and

19

cooling purposes. In Europe, energy certifications remain independent of embodied

energy and carbon emissions of building material, so it is not easy to establish a

relationship with results obtained from simulation tools such as CALENER.

(Srinivasan, Ingwersen, Trucco, Ries, & Campbell, 2014)performed a

comparison of two LCA tools, EIO-LCA and ATHENA Impact Estimator, to report the

conventional life cycle energy use of Rinker Hall located on the University of Florida

campus. ATHENA Impact Estimator provides cradle-to-grave process-based LCA

based on the location. EIO-LCA uses a country’s economy as a boundary of analysis

and does not include the evaluation of ecosystem goods and services in life cycle

energy. The study used construction drawings, bill of materials and commissioning

reports to understand input inventory. For the operational energy, the data were

collected from the concerned department and then extrapolated to a 75-year lifespan of

the building. Two major challenges for building stakeholders in conducting LCA for the

built environment are (a) establishing system boundaries and (b) the methodology for

data collection and data integrity. A significant difference exists for operational energy

between ATHENA Impact Estimator and EIO-LCA. For the EE EIO-LCA had three times

more value than ATHENA Impact Estimator. Fig. 2-2 describes the system boundaries

for the life cycle inventory and impact assessment methods used to assess the built

environment.

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Figure 2-2. System boundaries to evaluate the impacts on the built environment.

Source: (Srinivasan et al., 2014)

LCA Comparison of Different Materials

Construction material requires significant energy in its preparation. Some studies

have found that approximately 60% of overall life-cycle energy is in the form of

embodied energy, though it also depends on the life of the building and several other

factors. In Israel, the Negev Desert occupies 65% of the land area and has less than

8% of the population. A research study was performed involving LCEA (life- cycle

energy analysis) using the four methods of LCA. The system studied involved a student

dormitory building in the Negev Desert. The building had passive heating and cooling

features. The study analyzed embodied energy and operational energy for different

materials that could be used as an alternative to the building material used. For

operational energy, a thermal simulation was performed using the Quick II software

program. The study compared various building material with respect to their operational

energy and embodied energy for a duration of 25–30 years. It was found that houses

21

with low energy had the most embodied energy (40–60%), which could be reduced

significantly by substituting the walls of the house with alternative materials such as fly

ash blocks and hollow concrete blocks. The analysis showed that reinforced concrete-

based buildings have significantly high embodied energy followed by those made of

concrete blocks and AutoClaved Aerated Concrete (AAC) blocks. The stabilized soil

block (SSB) configuration, owing to its high thermal performance, had the lowest

cumulative energy among the different materials studied (Huberman & Pearlmutter,

2008). Figure 2-3 shows cumulative energy consumption over 50 years with different

wall type materials. The energy at the start of the plot shows the embodied energy of

the respective material.

Figure 2-3. Cumulative energy consumption with different wall materials over a life of 50

years. Source: (Huberman & Pearlmutter, 2008)

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Life cycle energy analysis (LCEA) is an approach that involves all energy inputs

involved in a building lifecycle. It involves energy used in manufacture, use, and

demolition phases. The manufacturing stage incorporates the transportation energy in it.

The operational energy includes all energy involved during the life cycle of the building

in providing thermal comfort and other necessities such as water supply, lighting and

powering appliances during the lifetime. The demolition phase includes the destruction

of buildings and transfer of the waste material to recycle plants or landfill sites. LCEA

gives an indication of the contribution of buildings towards greenhouse gas emissions,

but for a broader analysis, LCA of buildings is recommended. Studies have found that

operational energy represents 80–90% and embodied energy 10–20% of the energy

associated with a building (Ramesh, Prakash, & Shukla, 2010).

A study of four model single-family homes with a usable area of 98.04 m2 was

performed in Poznan, Poland. The houses were marked as A1 (conventional masonry

building), A2 (passive masonry building), B1 (conventional wooden building) and B2

(passive wooden building). The study assumed the life of all houses to be 100 years

and included all life cycle stages from the production of building material to final

disposal of demolition waste. Repair and replacement during the lifespan of the

buildings contribute the most to the mass flow of waste. Understanding the number of

inhabitants and the equipment used can lead to differences in energy consumption. The

study found that passive buildings have 3.6 times lower total energy in the entire cycle

compared to a conventional building. This is attributed to the low weight of the building

materials, less waste during the life cycle, lowest transport impact and low water and

energy consumption (Pajchrowski, Noskowiak, Lewandowska, & Strykowski, 2014).

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Example Studies Using LCA

(Junnila, Horvath, & Guggemos, 2006) did an LCA assessment of a typical new

office building in Finland and a new typical office building in Midwest region of the US.

For the office in Finland, design and construction plans were referred to quantify the

material and energy flows and for the operational energy, combined heat and power

utilized was used for analysis. This building accommodated more than two hundred

office workers. The building had four floors with most part used as office space and

some as commercial and laboratory space. The main structural components of this

building were reinforced structural concrete beam and column system. The study

included the substructure, foundation, structural frame, external envelope, roof,

mechanical services or 69 different building components. BOQs (Bill of Quantities) were

referred to get an estimate. The office selected in the U.S was a five-story building with

a gross area of 4,400 sqm with structural frame as steel-reinforced concrete column -

beam system with shear walls at the core. The study found that the Finnish building

uses a third less energy, and emits half the CO2, a third of NOx, and a fifth of PM10

when compared to the US building. The Operational energy for the Finnish building was

half of the US building. The differences in emissions are attributed to the different

energy mixes used in both the countries for energy production. In Finland, Natural gas

has a 67% share in electricity production whereas, for the US location, Coal and

Petroleum have a 21 and 40 percent share respectively.

BIM and LCA

In the past few decades, Building Information Modelling (BIM) witnessed a

growing interest in the construction sector. The benefits of using BIM technologies

involve resource savings in design, planning and execution stages. The first use of 3D

24

modeling started in the 1970s and by early 2000s pilot projects were introduced

(Penttilä, Rajala, & Freese, 2000) . The aim of BIM is to support architects and

designers in preplanning, clash detection, 3D visualization, estimation of quantities and

cost analysis. In recent times BIM technology has been used in assessing the life cycle

stages, maintenance activities, refurbishment, and deconstruction. Using BIM tools

information relevant to LCA can be easily stored and updated in a structured way

(Akbarnezhad, Ong, & Chandra, 2014).

Integrating BIM and LCA can play a significant role in promoting sustainable

construction. The improved collaboration between different stakeholders using BIM

reduces the impact of the buildings. BIM can integrate the information related to

environmental impacts and guides the designers in the selection of better materials.

Lack of environmental data, inadequate training of engineers on software tools,

uncertainty in LCA calculations and lack of standardization in LCA process are some of

the limitations associated with integrating BIM and LCA (Antón & Díaz, 2014). Studies

have found that integration of BIM with LCA is only partial and not whole. Currently, BIM

tools are used along with energy modeling tools like BEM and other LCA tools for

analysis. BIM is also used for quantifying the material in a building which can then be

used to assess the embodied energy and other impacts associated with the building.

Figure 2-4 shows the prospective framework for integrating LCA features into a BIM

tool. Using a single BIM tool reduces repeated work and can be linked to an artificial

intelligence model for operational energy assessment (Asadi, Nwodo, & Anumba,

2017).

25

Figure 2-4. Prospective framework for integrating LCA features into a BIM tool. Source:

(Asadi et al., 2017)

Significance of Embodied Energy

Embodied energy has a significant share in LCA of buildings. Studies conducted

across the world have found a 30–50% contribution by embodied energy depending on

location, climate, and type of construction (Dixit, 2017). Direct and indirect embodied

energy components lead to different system boundaries. Energy consumed in all site-

related activities whether onsite or offsite are direct embodied energy. Most direct

energy is consumed in site operations, operating equipment and tools, and transporting

material and labor to the site. The indirect embodied energy pertains to the energy

consumed in the manufacture and delivery of material, equipment and assemblies, etc.,

installed in a building. Embodied energy is generally reported in primary or delivered

energy. Delivered energy is the final energy delivered to the manufacturing site (e.g.,

electricity), and primary energy is the energy involved in producing the delivered energy

(e.g., raw energy of fossil fuels). Delivered energy remains a fraction of primary energy.

Primary energy is the true measure of energy involved in producing a product and can

give a true assessment of the environmental impact of delivered energy (Dixit, 2017).

26

Dixit (2017) stated that system boundaries can vary from case to case. A system

boundary can cover just the building structure and its surrounding components such as

landscaped areas and sidewalks and is generally referred to as initial embodied energy

(IEE). Another system boundary, which includes energy involved in maintenance and

repair activities once the building is occupied, is known as recurrent embodied energy

(REE). Most studies on embodied energy tend to avoid considering the REE and

demolition energy (energy consumed in demolition of building after its life). According to

(Dixit, 2017) it has been found in some studies that the amount of embodied REE can

be even higher than IEE associated with a building.

Components of Embodied Energy

The embodied energy of a product comprises of direct energy and indirect

energy. The energy that goes in the creation of the goods for the main manufacturing is

known as Indirect energy. The energy involved in the processing is called direct energy.

There are two different ways of embodied energy analysis. One is Input-Output (IO)

analysis and the other is Process analysis. Both these techniques have their own

limitations and advantages. Hybrid analysis techniques aim to collaborate the benefits

of both theses process and minimize the limitation. The accuracy of an embodied

energy analysis depends on the analysis process chosen (Treloar, 1997).

(Hammond & Jones, 2008) states that deciding system boundary is essential in embodied

energy calculations. There are three common boundaries: -

1. Cradle to grave: Cradle to grave is a detailed LCA analysis involving the study of energy and material used, and the pollution caused by their production in the environment during its whole life cycle.

2. Cradle to gate: Cradle to gate involves all the energy put in a product till it reaches the factory gates.

27

3. Cradle to site: Cradle to the site involves the embodied energy associated with a product till it reaches the site. There tends to be very little difference between cradle to site and cradle to gate if the material being shipped are high in density and have high embodied energy. When considering cradle to site as a system boundary.

Embodied Energy of Reinforced Concrete

Concrete is the second most utilized substance after water. (Goggins, Keane, &

Kelly, 2010) studied the embodied energy(EE) of reinforced concrete and the processes

involved in the manufacture of concrete along with the production of its component

material. Aggregate, binders, water, admixtures and reinforcement are the main

constituents of reinforced concrete. Cement is the main binder used in concrete and

contributes to over 50% of the embodied energy. Manufacturing of cement is a highly

energy-intensive process involving heating clay, silica and limestone to form clinker.

Aggregate constitutes up to 80% of the concrete and adds strength to the concrete mix.

Limestone is a major aggregate and its EE calculated based on a hybrid method using

Irish data was found to be 0.124 MJ/kg. To reduce the environmental impacts and

energy usage, using recycled concrete as an aggregate has been taken up by many

major projects. Wessex Water Operations Centre, UK met 40% of its requirement of

coarse aggregates from recycled concrete. The contribution of admixtures towards EE

of concrete is neglected as they are added in very small amounts while mixing.

The research by (Goggins et al., 2010) involved a study of a 3-story office

building in Ireland. The study highlighted that high energy is involved in the construction

of a reinforced concrete slab. A comparison was made between slabs with 50% GGBS

(Ground Granulated Blast Furnace Slag) and 0% GGBS. The floor with GGBS had 30%

less embodied energy compared to the slab with no GGBS.

28

Parameters for Embodied Energy Measurement

If the building designers keep themselves aware of the impact of building

materials, then building materials with low embodied energy can start getting preference

in construction designs. It would lead to reduced energy use and lesser carbon dioxide

emissions. (Dixit et al. 2010) Conducted a detailed literature review of peer-reviewed

and published bibliographic sources. The literature study found some major parameters

that influence the quality of embodied energy which is as follows: -

1. System boundaries: Defining system boundaries is very critical for embodied energy calculations. Studies also suggest having a consistent boundary selection method for better comparative assessment.

2. Method of embodied energy analysis: The main processes of embodied energy analysis are input/output analysis, hybrid analysis, process analysis and hybrid analysis. Amongst all these methods, process analysis is most widely used and is the most accurate.

3. The geographic location of study area: Raw material production, transport distances, fuel consumption, industrial processes and labor can bring a significant difference in the analysis of embodied energy. The differences in energy tariffs and variations in manufacturing processes influence the embodied energy values.

4. Age of data source: Technological advancements in manufacturing keep improving the efficiency of the processes involved. The fuel efficiency of transport system keeps improving with time. These developments can lead to significant differences in the analysis. Utilizing modern data source should be preferred in studying the carbon emissions and energy consumption.

5. The technology of manufacturing: Differences in manufacturing technologies and the type of energy used can lead to differences in energy consumption. Technological representativeness is important to maintain the quality of the data and eliminate any inconsistency in results.

Research Tools Used to Calculate Embodied Energy

EIO-LCA

EIO-LCA (Economic Input-Output based LCA) is an LCA tool developed at

Carnegie Mellon University. The tool is used to estimate the environmental impacts of

29

manufacturing construction material. EIO-LCA analysis found that the major

construction materials contributing the most to embodied energy and GHG emissions

are brick, windows, drywall, and concrete. These four materials account for 60-70% of

the total embodied energy for the buildings (Sharma, Saxena, Sethi, & Shree, 2011).

(Guggemos & Horvath, 2005; Kofoworola & Gheewala, 2009)mentions that there

are two main methodologies in LCA: process-based LCA and economic input-output

analysis based LCA known as EIO-LCA. The study conducted an LCA analysis to

compare the environmental impacts of steel and concrete framed buildings. The two

case study buildings were five-storied and had a floor area of 4400sq meter located in

the Midwestern US. The study used both process based LCA and EIO-LCA, and

evaluated the environmental impacts of each building during the complete life cycle of

the buildings. The analysis found that concrete frame structure has more energy and

emissions associated. The main reason for higher emission was found to be longer

installation process, formwork process, and relatively higher transportation energy. The

study used RS Means for cost estimation (Year 1999) and using price index modified

the estimate to the year of reference (1997) of EIO-LCA. The concrete building was

found to be low in cost but significantly higher in weight compared to the steel building

(1.5 times).

EIO-LCA overcomes some limitations of process-based LCA. The process-based

analysis is an intense analysis and involves mapping all associated inputs (e.g., energy)

and output (e.g., air emissions and water discharges). High data requirements and

flexible designing systems make it challenging to compare two LCA's using process-

based analysis. EIO-LCA overcomes the limitations of data requirement and defining a

30

boundary for the LCA. It provides a comprehensive analysis of different manufacturing

industries. A hybrid analysis combines the advantages of both Process-based LCA and

Input-Output based LCA. For the processes that have detailed information for typical

products or methods which are well represented by input-output analysis EIO-LCA is

preferred and for other products, the process-based analysis can be used. In

construction, EIO-LCA is preferred for the production of the material. For rest of the life

cycle assessment involving construction process, operation, maintenance, and

demolition process-based LCA is recommended. A study was conducted in Thailand to

calculate embodied energy of a building using EIO-LCA based spreadsheet model. The

cost of building materials was estimated using bill of materials. Energy intensities were

multiplied with cost of respective material including the wastage to calculate the total

embodied energy of the building (Kofoworola & Gheewala, 2009).

(Acquaye, Duffy, & Basu, 2008)Used national economic data of Ireland to

conduct an IO analysis and compare the embodied energy of different projects. The

energy intensities were determined per unit monetary output value. IO direct energy is

the energy consumed directly in the main construction process. The study used the

1998 national I-O data for Ireland. The Carbon dioxide emissions were calculated by

using emission factors as the research was conducted in 2008. The emission factors

account for the changes in fuel mix over the years. The study found bridge construction

to possess the embodied energy higher than the average of the construction sector.

House construction is low in energy intensity whereas heavy earthwork involved in

bridge construction makes it the most energy intense in construction.

31

EIO-LCA provides the embodied energy of a material concerning its economic

value. For the study, the US 2002 benchmark producer price model is used. It is the

latest available model in EIOLCA. The tool provides the energy involved in the raw

material extraction, raw material transportation and the process involved in

manufacturing the final product. Figure 2-5 shows the energy involved in the production

of steel worth $1million. This data is used for calculating embodied energy of reinforced

steel (EIO-LCA, 2016).

Figure 2-5. The energy involved in the production of steel worth $1million

Athena Impact Estimator

Athena Impact Estimator is an easy to use free LCA tool designed to assist

professionals in the construction industry. It provides a comparison of building designs

based on environmental impact assessment. To use the tool the quantity estimate has

to be prepared. The quantity takeoff from the Revit file is used as an input. The Impact

estimator has an option to select the relevant assembly for each category:

Foundations and Footings

32

Columns and Beams

Intermediate Floors

Walls

Windows

Roof The results from the tool incorporate the environmental impacts of the following

process:

Resource extraction and processing

Product Manufacturing

On-Site installation and construction activities

Transportation

Maintenance and replacement during the assumed life cycle of the building

Demolition and transportation to landfill

It does not include the operational energy of the building. The tool analyzes the inputs

and then provides cradle-to-grave implications like Global Warming Potential,

Acidification Potential, Ozone Depletion and Fossil Fuel Consumption. For the

embodied energy comparison, the total primary energy consumption is used.

The tool also needs location input, for this research the nearest available location is

selected which is Orlando (ImpactEstimator, 2018).

SEER

Indian Institute of Technology, Roorkee developed a tool named SEER

(Schedule of embodied energy rates) for embodied energy calculations for construction

material. The database has embodied energy details of common construction material

used in India such as brick, mortar, concrete and reinforced steel. The BOQ (Bill of

Quantities) is used to determine the quantity of different material and the respective

total embodied energy is calculated using the data from SEER (Chani, Rajasekar, &

Kumar, 2016).

33

Nevertheless, none of the research focused on comparing the embodied energy

of residential buildings in the U.S. and India. It is to be noted that the building materials

used in these two countries vary owing to differences in location and variability of locally

available construction material. The construction process also varies in both the

countries. This study involves study of EE of structural components, exterior envelope

and interior partitions for the two buildings.

34

CHAPTER 3 METHODOLOGY

The research compares embodied energy of two residential buildings located in

educational institutions in two different countries; one is Cyprus Hall located in the

University of Florida (UF) Campus, Gainesville, U.S and the other is Transit Housing

facility located in the Indian Institute of Technology (IIT), Roorkee Campus, India. This

study follows a two-step process:

1. Calculate and compare embodied energy 2. Recommending alternative material to reduce embodied energy

Figure 3-1 shows the order of activities involved in this study. The study starts with

estimating the quantity of building materials for both the buildings followed with

embodied energy calculations.

Figure 3-1. Methodology Flow Chart

During the study, several challenges were met particularly in the data acquisition

and methodology followed in EE calculation. These challenges are discussed in the

conclusion section.

35

Case Study Buildings

United States – Cypress Hall

Cypress Hall is a residential housing facility for the students of University of

Florida. It was built in 2014 and consists of two five story buildings with study lounge on

each floor. It is made of Concrete columns and beams as structural element and

gypsum board with insulation for partition walls. The significant part of the interior walls

is made up of masonry blocks. The floors are made of hollow core precast with concrete

topping. The exterior walls are made of Concrete Masonry Unit (CMU) blocks with the

façade finish of brick veneer, metal skin, and precast at various locations. The floors are

made of hollow-core precast concrete with concrete topping. The roof structure is made

of steel truss and metal deck with clay tiles on the top. A sizable portion of the building

has curtain walls in the exterior envelope. The floor area for Cypress Hall is 17,724 sf

for each floor and the ground floor has slab on grade. Figure 3-2 and Figure 3-3 are the

floor plans and 3D elevation from the Revit model of Cypress Hall respectively. Figure

3-4 shows the east elevation of Cypress Hall. The exterior wall has curtain walls,

precast panels, brick veneer, and metal panels.

36

Figure 3-2. First floor Revit model section of Cypress Hall

Figure 3-3. Structural image of Cypress Hall from the Revit model

37

Figure 3-4. East elevation of Cypress Hall

India – Transit Housing

The transit Housing is divided into six blocks named as Block B1-B6. To

calculate the embodied energy of the building, an estimate of quantities is required.

Available AutoCAD drawings and Bill of Quantities (BOQ) is used to estimate the

building materials. The BOQ contains information about earthwork, reinforced cement

concrete, brickwork, marble and granite work, woodwork (frames and trusses),

steelwork, flooring work, roofing work, waterproofing, plumbing, and firefighting

systems. The building has brick and concrete as its structural elements with interior

partition walls made of Autoclaved Aerated Cement (AAC) blocks.

AutoCAD drawings are used to calculate the area of the building. The total area

of the building is 18,257 square meters or 196,516 square feet. Figure 3-5 shows the

key plan of the site.

38

Figure 3-5. Key Plan of the Transit Housing

The blocks differ in area and number of floors. Figures 3.6 and 3.7 shows the

elevation plans of the blocks. Figure 3.8 shows the floor plan for level one of building

B1. Table 3-1 compares the different construction assemblies used in the two buildings.

Figure 3-6. North Elevation of Transit housing building

39

Figure 3-7. East Elevation of Transit Housing building

Figure 3-8. Level 1 Floor Plan for Building B1 (Transit Housing)

40

Table 3-1. Comparison of the different construction assemblies used in the two buildings

Assembly Cypress Hall Transit Housing

1. Foundation Concrete Foundation with

slab on grade

Concrete foundation

2. Structural

components

Concrete beams and

columns, concrete walls

Concrete beams and

columns

3. Roof Clay Roof tile with

insulation on structural

steel deck on light gauge

metal roof trusses

Concrete slab with clay

tiles.

*However, clay tiles are

not included in the BOQ.

4. Exterior envelope Curtain wall, brick veneer,

metal skin, precast

concrete panel

Brick with cement plaster.

*However, cement plaster

is not included in BOQ.

5. Interior Walls Gypsum Board, Concrete

block

AAC blocks

Scope and Limitation

The aim of the study is to compare the embodied energy per unit area of both the

buildings. The superstructure varies in both the countries. To maintain uniformity in the

comparison, only structural elements such as foundations, columns, beams, floors,

exterior envelope, and interior partition walls are considered for this study. Finishing

elements such as paint, floor finish, doors, and windows are not considered in this

study. Wall insulation is ignored in the study to maintain consistency. The main purpose

of insulation in walls is to reduce the operational energy of a building. Since this study

does not compare the operational energy, insulation material is not part of EE

calculation. Limiting the study to a few parameters brings the focus on them and

improves the analysis.

41

For the building in India, the BOQ is available which simplifies the embodied

energy calculations. The BOQ also represents the actual quantity of material that has

been ordered for the project including the wastage. However, it is noted that BOQ does

not include clay tiles (roof), cement plaster (walls), etc. For Cypress hall the BOQ is not

available, so Revit model had to be used for quantity takeoffs. An additional five

percentage of material has been added to account for wastage of material during the

construction process (Peterson, 2015). The study includes the exterior façade like brick

veneer, curtain walls, and precast walls. Doors and windows are not included in the

study due to unavailability of data.

The embodied energy (EE) values referred through EIO-LCA database are from

the producer model of 2002 whereas the Cypress Hall was constructed in 2014. The

producer model has the boundary of cradle-to-gate and the price is as per producer’s

perspective. Whereas RSMeans provides the cost of material from the purchaser’s

perspective which includes profit of the producer and the delivery cost.

The manufacturing processes improve over-time and the data used as input for EIO-

LCA and the actual year of construction have a difference of 12 years. Due to the

unavailability of a recent database, this research relies on the 2002 data. A major

limitation with EIO-LCA is that the data is not detailed for construction products.

Another limitation of this study is the difference of EE tools used. The SEER

database used for the Transit Housing facility in India is process-based whereas EIO-

LCA is an input-output based tool.

For the Cypress Hall, the quantity takeoff was done using Revit model. The

actual quantity ordered for the project can vary depending on the construction practices.

42

RSMeans has been used for calculating the prices with a standard conversion factor of

0.6 to approximate the price of 2002.

Athena Impact Estimator which is a process-based tool has been additionally

employed to study the EE associated with different components of. Cypress Hall. This

tool has standard construction assemblies for input. The lack of detailed input of

material remains a limitation of the tool.

The perimeter and shape of a building can significantly influence the embodied

energy of a building. For the same built up area, the per unit area EE can be different

depending on the shape of the building. However, for this study this consideration has

been ignored.

Quantity Takeoffs

Cypress Hall

The available Revit model is capable of generating a schedule of quantities for

most of the material except for steel reinforcement. For steel reinforcement, the as-built

drawings are used to estimate the quantity. Figure 3-9 shows the concrete quantity

take-off for column footing. The schedule can be easily exported to an Excel sheet for

further analysis. From the Revit model, the quantity take-off for the material is

compared. Table 3-2 represents the quantity take-off for Cypress Hall.

Transit Housing

For the Transit Housing building located in IIT Roorkee campus, the material

quantity estimation is done using the available BOQ. The BOQ provides quantities for

the reinforcement steel, structural steel, brick, AAC blocks, and concrete that has been

used in the building. The building has applications for different grades of concrete

43

varying from M25 to M40. Table 3-3 shows the quantity of material for the Transit

Housing.

Figure 3-9. Creating quantity take-off schedule using Revit

Table 3-2. Quantity take-off table for Cypress Hall

S. No Item Description Unit Quantity

1. Gypsum board sf 58,187 2. Metal studs lf 24,271 3. Reinforcement ton 234 4. Concrete cf 80,956 5. Brick sf 27,888 6. Concrete block 4

inch sf 675

7. Concrete block 6 inch

sf 31,03


sf 109,113


sf 1,731


sf 2,433

11. Metal deck sf 21,126 12. Truss system lf 2,460 13. Curtain wall sf 25,646 14. Clay tile sf 23,238

44

Table 3-3. Material quantity takeoff from the available BOQ for Transit Housing

S. No Item Description Unit Quantity

1. Steel reinforcement kg 1,668,223

2. Concrete M30 Cu.m 13,823

3. Concrete M35 Cu.m 10

4. Concrete M40 Cu.m 691

5. Concrete M25 Cu.m 15,204

6. Steel work kg 85,034

7. Brick Cu.m 266

8. AAC block Cu.m 334

Calculation of Index Factor:

Time adjustment using the Historical Index:

(Index for Year A/Index for Year B) X Cost in Year B = Cost in Year A

Using the above formula and referring to the RS means cost index from Appendix A, the

cost index factor is calculated as shown below:

(Index for Year 2002/Index for Year 2018) = 59.6/100 ≈0.6

Using the calculated adjustment factor, the cost of the material is calculated for

the year 2002. Table 3.4 shows the cost in year 2002 after using the cost index factor

on the cost of year 2018.

Cost Estimation Using RS Means

Since the EIO-LCA is based on an economic input, a cost estimate is prepared

using RS Means online. First, the cost estimate for all the materials is prepared as per

the rates of 2018. To calculate the price of the same material in the year 2002 RS

Means historical cost index is referred (Appendix A).

45

Table 3-4. Cost estimates

S. No Item Description Unit Quantity Cost in 2018

Cost in 2002

Total Price ($)

1. Gypsum board sf 58,187 $0.31 $0.186 10,822 2. Metal studs lf 24,271 $8.26 $4.95 120,141 3. Reinforcement Ton 234 $942 $565 132,210 4. Concrete cf 86,117 $5.15 $3.09 266,101 5. Brick sf 27,888 $2.91 $1.74 48,693 6. Concrete block 4

inch sf 675 $2.17 $1.30 880


sf 3,103 $2.77 $1.66 5,157


sf 109,113 $2.98 $1.78 195,094


sf 1,731 $3.43 $2.05 3,562


sf 2,433 $4.69 $2.81 6,846

11. Metal deck sf 21,126 $1.65 $1 21,126 12. Truss system lf 4,819 $3.68 $2.21 10,650 13. Curtain wall sf 25,646 $41.52 $24.92 638,906 14. Clay tile sf 23,238 $5.13 $3.07 71,340

Embodied Energy Calculations

Cypress Hall (Using EIO LCA)

Table 3-5 shows the embodied energy associated with construction materials of

Cypress hall from EIO-LCA database. The EE values are associated with material worth

$1 Million.

The EIO-LCA model uses the 2002 producer model as a benchmark model. To

calculate the embodied energy of the building, a quantity takeoff using the Revit model

is completed. EIO-LCA database is referred for calculating the embodied energy for

Cypress Hall for respective material. Using the embodied energy values from Table 3-5

and the cost estimate from Table 3-4 the total embodied energy is calculated as shown

in Table 3-6.

46

Table 3-5. Embodied energy of construction material of $1Million

Item Description Embodied Energy(TJ) NAICS

Brick 31.4 32712 A

Ready Mix Concrete 17.1 327320

Glass/Curtain Wall 37.1 327211

Lime and Gypsum product 44.7 3274A0

Concrete Block 17.1 327330

Steel 43.3 331110

Cypress Hall (Using Athena Impact Estimator)

Athena Impact Estimator uses the dimensions and type of assembly as input for

calculating the various environmental impacts. The tool has separate section for each

assembly.

For columns and beams, the bay area is required as input. There are 98 different

columns in Cypress Hall. Therefore, an average bay area is calculated as 17,724/98 =

180 sf. The computed embodied energy is multiplied by the total number of floors. For

the intermediate floors, the option of hollow core slab is selected. The interior walls are

made of gypsum board with metal studs and concrete blocks. The exterior walls are

made of CMU blocks with metal skin, precast, and paint. Curtain walls have a significant

share in exterior envelope too. For the roof, the option of open web-joist is selected

with asphalt-cellulose on the top. Athena Impact Estimator has the option to input

different types of exterior walls to the building. Table 3.7 shows the embodied energy

calculations for Cypress Hall based on Athena Impact Estimator tool.

47

Transit Housing

For the Transit Housing facility at IIT Roorkee, the embodied energy calculation

is done using the BOQ and the respective embodied energy for each material from the

SEER database. The calculation is shown in Table 3.7.

Table 3-6. Total embodied energy calculation for Cypress Hall using EIO-LCA

S. No

Item Description

Unit NAICS Cost in 2018

Cost in 2002

Total Price ($)

Embodied Energy in MJ per $

Total Embodied energy(MJ)

1. Gypsum Board sf 3274A0 $0.31 $0.186 $10,822 44.7 483,743

2. Metal studs lf 331110 $8.26 $4.95 $120,141 43.3 5,214,139

3. Reinforcement ton 331110 $942 $565.00 $132,210 43.3 5,737,914 4. Concrete cf 327320 $5.15 $3.09 $266,101 23.5 6,253,385 5. Brick sf 32712A $2.91 $1.74 $48,693 31.4 1,528,942 6. Concrete Block

4 inch sf 327330 $2.17 $1.30 $880 17.1 15,037

7. Concrete Block 6 inch

sf 327330 $2.77 $1.66 $5,157 17.1 88,187


sf 327330 $2.98 $1.78 $195,094 17.1 3,336,108


sf 327330 $3.43 $2.05 $3,562 17.1 60,917


sf 327330 $4.69 $2.81 $6,846 17.1 117,074

11. Roof Metal Deck

sf 331110 $1.65 $1.00 $21,126 43.3 916,868

12. Truss System sf 331110 $3.68 $2.21 $10,650 43.3 462,210 13. Curtain Wall sf 327211 $41.52

$24.92 $638,906 37.1 23,703,412

14. Clay Tile (Roof) sf 32712B $5.13 $3.07 $71,340 19.5 1,391,130 Total 49,309,066

48

Table 3-7. Embodied energy calculations for Cypress Hall from Athena Impact Estimator

S. No Material Embodied Energy (MJ)

1. Concrete (foundations/footings) 1,640,000

2. Concrete column/beam 10,384,288

4. Intermediate floors 4,620,000

5. Walls 1,520,000

8. Roof system 6,910,000

Total 22,190,000

Table 3-8. Total embodied energy calculation for Transit Housing

S. No Item Description Unit Quantity Embodied Energy

per unit

quantity(MJ)

Total

Embodied

Energy (MJ)

1. Steel reinforcement kg 1,668,223 41.92 69,931,908

2. Concrete M25 Cu.m 15,204 2,668.30 40,569,178

3. Concrete M30 Cu.m 13,823 2,747.00 37,971,781

4. Concrete M35 Cu.m 10 2,828.00 28,280

5. Concrete M40 Cu.m 691 2,908.00 2,009,428

6. Steel work kg 85,034 33.62 2,859,055

7. Brick Cu.m 266 2,422.00 603,078

8. AAC block Cu.m 334 718.75 240,062

Total 154,212,770

49

CHAPTER 4 RESULTS AND DISCUSSION

Embodied Energy Comparison

The total embodied energy of both buildings is calculated by adding the

embodied energy of each component considered for the study. The unit of comparison

is the total embodied energy per unit area, i.e. MJ/sf. The perimeter of a building also

influences the embodied energy since the area of the exterior envelope can change for

the same built-up area.

Embodied Energy Analysis for Cypress Hall Using EIO-LCA

The surface area of Cypress Hall is 17,724 sf for each floor. The building has five

floors with a total area of 88,620 sf. The total embodied energy calculated is 49,309,066

MJ or 49.3 TJ and the embodied energy per sf is 556 MJ. Figure 4.1 represents

embodied energy share for different materials used in Cypress Hall as calculated from

EIO-LCA. From the bar graph, it can be noted that curtain walls contribute to maximum

embodied energy.

Figure 4-1. Embodied energy share for different materials used in Cypress Hall from

EIO-LCA

0.48

17.40

1.96 6.25 1.52 3.61 0.91 0.46

23.70

1.39

Embodied Enrgy (TJ)

50

Embodied Energy Analysis for Cypress Hall Using Athena Impact Estimator

Using Athena Impact Estimator for Cypress Hall, the total Embodied energy is

22.19 TJ. The Embodied energy per square foot is 250 MJ. Figure 4.2 represents

embodied energy share for different elements used in Cypress Hall from Athena Impact

Estimator. Figure 4.3 shows that reinforced steel and concrete columns and beams

contributes to the highest amount of embodied energy in the building.

Figure 4-2. Embodied energy share for different elements used in Cypress Hall from Athena Impact Estimator

Embodied Energy of Transit Housing Using SEER

The total surface area of Transit housing is 196,516 sf including all six blocks.

The total embodied energy calculated is 154,212,770 MJ or 154.2 TJ and the embodied

energy per sf is 784 MJ. The Transit housing structure has steel and concrete as the

major embodied energy contributing elements. The combined share of both steel and

concrete is 97% in the building. The brick masonry and AAC blocks used in the building

have a negligible contribution. Fig 4.3 shows embodied energy share of different

material of the building.

1.64 1.52

7.5

4.62

6.91

FOUNDATION WALLS COLUMNS AND BEAMS

FLOORS ROOF

Embodied Energy(TJ)

51

Figure 4-3. Embodied energy share for different materials used in Transit Housing using

SEER

Observations

The embodied energy per square feet for the Transit Housing and Cypress Hall

(using EIO-LCA and Athena) is shown in Figure 4.4. The EE of Transit Housing is on

the higher side compared to Cypress Hall. The EE results from ATHENA are less than

half compared to EIO-LCA. Some of the main reasons for this difference can be

attributed to the high EE value of curtain walls derived from EIO-LCA, the EIO-LCA

database being 16 years old, and use of a constant factor derived from RS Means for all

the products as discussed in the Scope and Limitations section.

A closer analysis of the data shows that reinforced steel and concrete have a

significant share of embodied energy in both the buildings. Figure 4.5 shows the

comparison of the embodied energy of steel reinforcement and concrete in MJ/sf

between the two buildings. For both the material the EE is higher for Transit Housing.

69.93

80.57

2.85 0.60 0.24

STEEL CONCRETE STEEL WORK BRICK AAC BLOCK

Embodied Energy(TJ)

52

Figure 4-4. Embodied energy (MJ/sf) for Cypress Hall and Transit Housing

Figure 4-5. Comparison of EE contribution of reinforced steel and concrete in both the buildings

Comparing amount of concrete and steel reinforcement used in both the

buildings is essential for better understanding of results. Figure 4-6 and Figure 4-7

compares the quantity of steel reinforcement and concrete quantities per unit area

respectively.

556

250

784

CYPRESS HALL(EIO-LCA) CYPRESS HALL(ATHENA) TRANSIT HOUSING(SEER)

Embodied Energy (MJ/sf)

410

70.56

355

64.74

TRANSIT HOUSING CYPRESS HALL


Concrete Steel

53

Figure 4-6. Comparing concrete used in the buildings per unit area

Figure 4-7. Comparing steel reinforcement used in the buildings per unit area

The amount of concrete and steel reinforcement used in Transit housing per unit

area is almost three times of Cypress Hall. It can be analyzed that the excess quantities

of concrete and reinforced steel used for Transit Housing relative to the Cypress Hall

lead to the differences in EE values as seen in Figure 4.5.

0.91

2.60

CYPRESS HALL TRANSIT HOUSING

Concrete per unit area(cf/sf)

5.26

18.70


Steel reinforcement (lb/sf)

54

The EE energy values of steel and concrete also vary in both the countries.

Figure 4-8 shows the comparison of the EE energy values of steel (MJ/lb) and

concrete(MJ/cf). The EE values for both steel and concrete are higher on the Indian

side. The amount of steel (lb/sf) and concrete (cf/sf)) used in Cypress Hall is less than

Transit housing. Also, the EE for steel (MJ/lb) and for concrete (MJ/cf) is less for

Cypress Hall, hence the overall EE contribution from steel and concrete is less for

Cypress Hall compared to Transit Housing.

Figure 4-8. Comparison of EE values of steel and concrete

The perimeter of building envelope can influence the embodied energy. Figure 4-9

shows the comparison of EE of Cypress hall and Transit housing per square feet of

exterior envelope.

12.27

67

19.05

75.55

STEEL(MJ/LB) CONCRETE(MJ/CF)

EE Comparison of Steel and Concrete

US INDIA

55

Figure 4-9. Embodied energy comparison of exterior envelope

Cypress hall has significantly high EE in the envelope when compared to the Transit

housing. From the table 4-1 shown below it can be analyzed that curtain wall has a

significant share of EE. If the envelope consists only of brick veneer and CMU block the

EE of Cypress hall will be reduced by 75%.

Table 4-1 Embodied energy of envelope

Cypress Hall Area(sf) EE(MJ per sf of

wall area)

Transit

Housing

Area(sf) EE (MJ per sf of

wall area)

CMU Block

with Brick

28,619 84.00 Brick 11,646 51.78

Precast Wall 8,444 29.70

Curtain Wall 23,315 1016.70

436.54

51.78



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Comparing EE of Interior Wall material

The interior walls of Cypress hall are majorly of two types, eight-inch masonry

and gypsum board with metal studs. The interior walls of Transit housing are made of

AAC blocks. Figure 4-10 compares the EE per unit square feet of wall area for masonry

block used in Cypress hall with AAC blocks used in Transit housing. It can be deduced

that the masonry block has significantly high EE compared to the AAC blocks. If the

interior masonry blocks are replaced with AAC blocks the EE of Cypress Hall will be

reduce by 7%.

Figure 4-10. Embodied energy comparison of interior walls of both buildings

Using a process-based EE tool (Athena Impact Estimator) and Input-output based tool

(EIO-LCA) gives a better analysis. Both the tools have their own advantages and

limitations, Athena Impact Estimator is an easy to use and quick way of doing an EE

analysis. It involves the input of dimensions of different construction assemblies. Figure

4-11 compared the EE per unit area as calculated using the Athena Impact Estimator

71.4

2

CONCRETE BLOCK(CYPRESS) AAC BLOCK(TRANSIT HOUSING)


57

and EIO-LCA. The EE value derived from EIO-LCA is more than double that of

ATHENA Impact Estimator.

Figure 4-11. Embodied energy comparison of Cypress Hall between EIO-LCA and

Athena Impact Estimator

A comparison is drawn between the EE values of different construction

assemblies derived from EIO-LCA and Athena Impact Estimator is shown in Figure

4-12. For walls (exterior and interior) the EE value derived from EIO-LCA is around 20

times more than the value from Athena Impact Estimator. One main reason is attributed

to the high EE of curtain walls when calculated using EIO-LCA.

556

250

EIO-LCA ATHENA


58

Figure 4-12. Comparison of EE values derived from EIO-LCA and Athena Impact Estimator for different assemblies of Cypress hall

Recommendations

Using this comparative study a few recommendations can be drawn for the designers

looking to reduce EE of a building: -

1. Using AAC Blocks in the U.S buildings instead of masonry blocks can reduce embodied energy of interior walls by ninety percent.

2. Using Hollow core precast slabs in India to reduce reinforced steel and concrete quantity in floors.

3. Designing the buildings in an efficient way to reduce steel and concrete quantities to bring down the total EE of the buildings.

0.97 1.507.65

2.76

34.54

1.64 7.55 4.62 6.91 1.52

FOOTING AND FOUNDATION

COLUMNS AND BEAM INTERMEDIATE FLOORS ROOF WALLS

Embodied Energy(TJ)

EIO-LCA ATHENA

59

CHAPTER 5 CONCLUSION

This study analyzed the embodied energy associated with two residential

buildings located on educational campuses in two different countries, the U.S and India.

The buildings differ in the type of construction material. The embodied energy was

calculated using the quantity estimate and embodied energy tools. The study found the

EE per unit area for Cypress Hall (U.S) is 556 MJ/sf from EIO-LCA and for the Transit

Housing building (India) the calculated EE is 784 MJ/sf. The difference between the EE

of both buildings is of 228 MJ/sf. Considering the structural elements steel

reinforcement and concrete, both had significantly high EE for Transit housing

compared to Cypress Hall. One of the major reason for the difference is the use of

precast hollow core concrete in the intermediate floors of Cypress Hall. The hollow core

precast concrete utilizes less concrete and steel compared to a regular reinforced slab.

The exterior walls of Cypress Hall which included the curtain walls, precast

panels and CMU blocks with brick veneer surpassed the EE of exterior walls of Transit

Housing which are made of locally available bricks. A major contribution for this

difference can be associated with significantly high EE value of curtain walls derived

using EIO-LCA.

Future work. This study highlights the EE associated with different components

of a building. The comparison of EE values of the buildings located in two different

countries remains an important aspect of this study. However, there were limitations to

this study owing to differences in the tools used and overtime change in manufacturing

technologies. For future studies following suggestion are recommended:

60

1. EE Tools: The database used for a comparative study should be as latest as possible. For the AAC fraternity, it is important to develop easy to use LCA tools and keep them updated.

2. Research in comparing construction assembly: Research should be conducted in comparing individual components of construction in different countries. It is easier to analyze and recommend a material with low EE if a detailed comparative study has been conducted.

3. Collaboration between different design tools: With BIM and other LCA tools becoming an integral part of construction processes, there remains scope for integrating these two into the structural design tools. A complete integration can reduce the impact of a component of a building from the design stage itself.

4. Comparing manufacturing technology: As technology progresses there are efficient processes being invented in different corners of the world. Cement and steel are major components of construction industry everywhere around the world. Understanding and comparing manufacturing processes can better the EE studies.

61

APPENDIX A CYPRESS HALL 3D PERSPECTIVES

Figure A-1. SE Perspective

Figure A-2. NW Perspective

62

Figure A-3. SW Perspective

Figure A-4. NW Perspective

63

Figure A-5. Roof Section for Cypress Hall

64

APPENDIX B ATHENA RESULTS AND COST INDEX

Figure B-1. ATHENA Impact Estimator Report

65

Figure B-2. RSMeans Cost Index

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BIOGRAPHICAL SKETCH

Vishal is currently doing his master’s in construction management at M. E. Rinker

School of Construction Management at University of Florida. He has been involved in

research work since his sophomore year of Civil Engineering in India. He received his

B.E(Hons) in Civil Engineering from Birla Institute of Science and Technology, Pilani in

2014. After working in construction industry for two years he decided to enhance his

educational background and joined the construction management master’s program at

University of Florida.

At UF, he has been working with Dr. Ravi Srinivasan since fall 2017. He is very

enthusiastic about technological developments in sustainable construction. In future, he

aims to utilize his education and experience to develop affordable housing and better

communities for under privileged people around the globe.

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