Energy optimization through building envelope Performance in Hotels

ENERGY OPTIMIZATION THROUGH BUILDING ENVELOPE PERFORMANCE IN HOTELS

Coordinators: Dr. Vibhuti Sachdev, Professor, SSAA Ms. Parul Munjal, Associate Professor, SSAA

RESEARCH PAPER IN ARCHITECTURE 2014-2015

Submitted by: NALIN BHATIA 04416901611/SSAA/B.Arch./11

SUSHANT SCHOOL OF ART AND ARCHITECTURE

ACKNOWLEDGEMENT I would like to express my gratitude to my guide Prof. Anurag Roy and Prof. Himanshu Sanghani whose expertise, understanding and generous guidance and support made it possible for me to work on a topic of my interest. Without his suggestions and encouragement, this research paper would not have been possible.

I would also like to thank my dissertation coordinators Dr. Vibhuti Sachdev and Ms. Parul G. Munjal whose constant moral support and guidance allowed me to finish my report.

I would like to thank Mr. Manish Negi, (Ex. Project Manager) for providing me the necessary drawings of a hotel for my case study and allowing me to model it.

My deep sense of gratitude to my batch mates and family members for their constant support, concern and encouragement that motivated me to move forward and accomplish my task successfully.

Dissertation | Energy Optimization through Building Envelope Performance in Hotels|

ABSTRACT Hotels are an integral building typology when it comes to commercial building design and requires special design criteria from site selection to exteriors to interiors as it has a range of different functional spaces like the lobby, restaurant kitchen, rooms etc. Hotels and resorts are the largest consumers of energy from the building stage to the running stage with complex installations, customers demanding high levels of servicing, the latest technology, and the highest standards of comfort. High levels of comfort are currently linked with a soaring exploitation of natural resources, such as water and construction materials, as well as the consumption of vast amounts of energy from non-renewable resources. Hence, today hotel industry is considered to be one of the leading contributors to environmental degradation and global warming.

In todayâ€&#x;s world, where everyone is talking about green architecture and buildings being sustainable, in hotels, attention is only being paid on the systems and products installed within the building and the shell of the building, i.e., the envelope is often overlooked as most of the thought is placed on the exterior aesthetics only.

The research paper is an attempt to identify the impact of the buildingâ€&#x;s envelope on the overall energy consumption and the global warming potential as when it comes to construction planning; many hotels are focused on marketability and attracting business. It seeks to create awareness among architects, engineers and clients about the growing need for sustainability and the energy savings that can be done by the employment of energy efficient materials and practices within the buildingâ€&#x;s envelope.

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

CONTENTS ABSTRACT ........................................................................................................................................... 4 LIST OF FIGURES .............................................................................................................................. 8 LIST OF TABLES .............................................................................................................................. 11 CHAPTER 1:

INTRODUCTION................................................................................................... 12

1.01 Building Energy Scenario in India .................................................................................... 12 1.02 Energy use in hotels .......................................................................................................... 13 1.1 Objectives ................................................................................................................................... 15 1.2 Significance of Study .................................................................................................................. 16 1.3 Research Methodology ............................................................................................................... 16 1.4 Research Questions ..................................................................................................................... 17 1.5 Limitations of Research .............................................................................................................. 17 CHAPTER 2:

LITERATURE REVIEW....................................................................................... 18

2.1 Building Envelope ...................................................................................................................... 18 2.2 Embodied Energy........................................................................................................................ 19 2.2.1 Importance of Embodied Energy ..................................................................................... 21 2.3 Operational Energy ..................................................................................................................... 22 2.3 Life Cycle Assessment ................................................................................................................ 24 CHAPTER 3:

TYPES OF BUILDING ENVELOPE TREATMENTS ...................................... 27

3.1 Masonry wall systems ................................................................................................................. 27 3.1.1 Brick................................................................................................................................. 27 3.1.2 Stone ................................................................................................................................ 27 3.1.3 Concrete Blocks ............................................................................................................... 27 3.2 Cavity wall .................................................................................................................................. 27 3.3 Jali ............................................................................................................................................... 28 3.4 Curtain wall................................................................................................................................. 29 3.5 Double-skin Envelope ................................................................................................................. 30 CHAPTER 4:

CASE STUDIES OF BUILDING ENVELOPES ................................................. 32

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

4.1 Traditional Building Envelopes: Havelis of Shekhawati ............................................................ 32 4.2 Traditional Building Envelopes: Hawa Mahal ............................................................................ 34 4.3 Modern Building Envelope: Terry Thomas Office building....................................................... 35 4.4 Modern Building Envelope: Transport Corporation of India, Gurgaon...................................... 38 4.1.4 Combination of modern and traditional practices in envelope: India International Centre, New Delhi.................................................................................................................................................. 40 CHAPTER 5:

SECONDARY CASE STUDIES............................................................................ 43

5.1 Case Study 1: Embodied Energy of Building Envelopes and its Influence on Cooling Load in Typical Indonesian Middle Class Houses ......................................................................................... 43 5.2 Case Study 2: Assessing impact of material transition and thermal comfort models on embodied and operational energy in vernacular dwellings (India) .................................................................... 47 5.3 Case Study 3: Embodied Energy and CO2 coefficients for NZ Building Materials by Andrew Alcorn ............................................................................................................................................... 51 CHAPTER 6:

PRIMARY CASE STUDY AND ANALYSIS ...................................................... 53

6.1 Methodology ............................................................................................................................... 53 6.2 Analysis of Operational Energy .................................................................................................. 56 6.2.1 Case 1: The original L shaped Plan.................................................................................. 56 6.2.2 Case 2: The Courtyard Plan ............................................................................................. 58 6.2.3 Case 3: Singly loaded Corridor Plan ................................................................................ 60 6.2.4 Case 3: Doubly loaded Corridor Plan .............................................................................. 62 6.3 Analysis on changes in envelope material .................................................................................. 64 6.3.1 Option A: Burnt Clay bricks with paint ........................................................................... 64 6.3.2 Option B: Curtain Wall System ....................................................................................... 69 6.3.3 Option C: Stone Cladding ................................................................................................ 74 6.3.4 Option D: Cavity Wall ..................................................................................................... 79 6.4 Effect of Insulation ..................................................................................................................... 85 6.5 Effect of Variation in Envelope .................................................................................................. 87 CHAPTER 7:

CONCLUSION AND RECOMMENDATIONS .................................................. 90

7.1 Conclusion based on primary case study .................................................................................... 90 7.2 Recommendations for Architects/Designers/Engineers:............................................................. 94

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

BIBLIOGRAPHY ............................................................................................................................... 96 APPENDIX 1: LIST OF EMBODIED ENERGIES OF COMMON MATERIALS .................... 98

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

LIST OF FIGURES Figure 1.1: Typical energy end use in a hotel. Source - Energy & Environmental Performance Index for Buildings: Luxury Hotels In India (Bansal and Roy) ...................................................................... 15 Figure 2.1: Share of different components in total embodied energy. Source: (Indian Buildings Congress, 2008). ................................................................................................................................... 20 Figure 2.2: Comparison of Initial to Recurring Embodied Energy for Wood Structure Building Over a 100-Year Lifespan. Source: (Cole and Kernan, 1996). ........................................................................ 20 Figure 2.3 Embodied and Operational Energy Relationship. (Source: Nancy W. Stauffer, MIT Energy Initiative,2009) ...................................................................................................................................... 21 Figure 2.4: Comparison of annual air-conditioning energy for the traditional dwelling with varying wall configurations and climatic zones, with ASHRAE 55 as the reference model. Source: (Praseeda, Mani and Venkatrama, 2013) ............................................................................................................... 23 Figure 2.5: Stages of Life Cycle Assessment. Source: (Blanchard & Reppe, 1998) (Hsu, 2009) (Kulkarni & Ramachandra, 2006) (Punmia, Jain, & Jain, 2005), (2009)............................................ 24 Figure 2.6: Energy consumption due to different phases in a buildings life cycle. Source: Kofoworola and Gheewala ....................................................................................................................................... 25 Figure 2.7: Breakdown of embodied energy due to different materials. Source: Kofoworola and Gheewala .............................................................................................................................................. 26 Figure 3.1: Cavity wall section. Source: http://www.thewarmergroup.co.uk/insulation/homeowners/cavity-wall-insulation#.VCUH-vQW39U28 Figure 3.2: Jali at Tomb of Salim Chisti, Fatehpur Sikri, Agra. Source: http://en.wikipedia.org/wiki/Tomb_of_Salim_Chishti .......................................................................... 29 Figure 3.3: Godrej Green Business Centre in Hyderabad with Jali facade. Source: http://www.infrawindow.com/green-spaces/godrej-green-business-centre-hyderabad_5/perforatedwalls_14 ................................................................................................................................................ 29 Figure 3.4: Jali at Sidi Saiyyed Mosque. Source: http://en.wikipedia.org/wiki/Sidi_Saiyyed_Mosque 29 Figure 3.5: A typical curtain wall section. Source: http://www.aluk.co.uk/sl52-curtain-walling.php .. 30 Figure 3.6: Typical Double-Skin Facade configuration. Source: http://www.fenestrapro.com/seeingdouble-part-i-the-concept-of-a-double-skin-facade-2/ ......................................................................... 31 Figure 4.1: Facade treatment in a typical Haveli (Source:http://www.wackywanderlust.com/2014/01/open-art-gallery-of-shekhawati-explores.html) . 32 Figure 4.2: Ground and First Floor plans of the haveli (Source: http://www.unige.ch/cuepe/html/plea2006/Vol1/PLEA2006_PAPER978.pdf) ..................................... 32 Figure 4.3: A typical jharokhas in a haveli. Source: http://www.photonicyatra.com/Destinations/IndiaRajasthan-Jodhpur................................................................................................................................ 33 Figure 4.4: The Venturi Effect through the hole of a Jali ..................................................................... 33

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

Figure 4.5:The front elevation of the palace. Source: http://theyoungbigmouth.com/2014/04/05/hawamahal-jaipur/ ........................................................................................................................................ 34 Figure 4.6: Jharokhas on the facade. Source: http://theyoungbigmouth.com/2014/04/05/hawa-mahaljaipur/.................................................................................................................................................... 34 Figure 4.7: Stained glass openings. Source: http://theyoungbigmouth.com/2014/04/05/hawa-mahaljaipur/.................................................................................................................................................... 35 Figure 4.8: South courtyard elevation. Source: http://escholarship.org/uc/item/4vq936rc#page-57 ... 36 Figure 4.9: Fixed exterior overhangs. Source: http://escholarship.org/uc/item/4vq936rc#page-57 .... 37 Figure 4.10: Automated exterior venetian blinds. Source: http://escholarship.org/uc/item/4vq936rc#page-57 .............................................................................. 37 Figure 4.11: TCIL building, Gurgaon. Source: http://high-performancebuildings.org/tcil.php .......... 38 Figure 4.12: Wall Section. Source: http://high-performancebuildings.org/tcil.php ............................. 38 Figure 4.13: Arrangement of openings. Souce: http://high-performancebuildings.org/tcil.php .......... 39 Figure 4.14: Larger windows facing the courtyard. Source: http://highperformancebuildings.org/tcil.php........................................................................................................ 39 Figure 4.15: The IIC complex. Source: http://www.iicdelhi.nic.in/Home.aspx?TypeID=1030 ........... 40 Figure 4.16: China Mosaic tiles for roof finish. Source: Author .......................................................... 41 Figure 4.17: : Rugged quartzite stone wall: Source: Author ................................................................. 41 Figure 4.18: Hollow core concrete blocks used for external wall. Source: Author .............................. 41 Figure 4.19: Large windows with wooden wool panels. Source: Author ............................................. 41 Figure 4.20: : Use of jali screen throughout the guestroom facade. Source: Author ............................ 42 Figure 5.1: Floor plan of the dwelling. Source: Praseeda, Mani and Venkatrama, 2013. ................... 48 Figure 5.2: Comparison of annual air-conditioning energy for the traditional dwelling with varying wall configurations and climatic zones, with ASHRAE 55 as the reference model (Source: Praseeda, Mani and Venkatrama, 2013) ............................................................................................................... 50 Figure 6.1: Courtyard shape plan shaped plan with singly loaded corridor. Source: Author ............... 53 Figure 6.2: The original L shaped Plan. Source: Project Manager ...................................................... 53 Figure 6.3: Doubly loaded corridor plan. Source: Author .................................................................... 53 Figure 6.4: : Singly loaded corridor plan. Source: Author .................................................................... 53 Figure 6.5: The original L shaped Plan. Source: Project Manager ...................................................... 56 Figure 6.6: Variation of operational with orientation for L shaped plan. Source: Author .................... 57 Figure 6.7: The courtyard plan. Source: Author ................................................................................... 58 Figure 6.8: Variation of operational with orientation for courtyard shaped plan. Source: Author ....... 59 Figure 6.9: The Singly loaded corridor plan. Source: Author............................................................... 60 Figure 6.10: Variation of operational with orientation for singly loaded corridor plan. Source: Author .............................................................................................................................................................. 61 Figure 6.11: The Doubly loaded corridor plan. Source: Author ........................................................... 62

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

Figure 6.12: Variation of operational with orientation for doubly loaded corridor plan. Source: Author .............................................................................................................................................................. 63 Figure 6.13: The Doubly loaded corridor plan. Source: Author ........................................................... 64 Figure 6.14: Embodied Energy share of Building Envelope Componet for option A. Source: Author 66 Figure 6.15: Embodied Energy share of Building Envelope Material for option A. Source: Author ... 66 Figure 6.16: Variation of operational energy with orientation for option A. Source: Author. ............. 68 Figure 6.17: Energy v/s years - option A. Source: Author.................................................................... 69 Figure 6.18: Embodied Energy share of Building Envelope Component for option B. Source: Author. .............................................................................................................................................................. 71 Figure 6.19: Embodied Energy share of Building Envelope Material for option B. Source: Author ... 71 Figure 6.20: Variation of operational energy with orientation for option B. Source: Author............... 73 Figure 6.21: Energy v/s years - option B. Source: Author. ................................................................... 74 Figure 6.22: Embodied Energy share of Building Envelope Component for option C. Source: Author. .............................................................................................................................................................. 76 Figure 6.23: Embodied Energy share of Building Envelope Material for option C. Source: Author ... 76 Figure 6.24: Variation of operational energy with orientation for option C. Source: Author............... 78 Figure 6.25: Energy v/s years - option C. Source: Author. ................................................................... 79 Figure 6.26: Embodied Energy share of Building Envelope Componet for option D. Source: Author. .............................................................................................................................................................. 81 Figure 6.27: Embodied Energy share of Building Envelope Material for option D. Source: Author. .. 81 Figure 6.28: Variation of operational energy with orientation for option D. Source: Author. ............. 83 Figure 6.29: Energy v/s years – option D. Source: Author. .................................................................. 84 Figure 6.30: Variation of energy with envelope options. Source: Author ............................................ 85 Figure 6.31: Variation of operational energy with insulation. Source: Author..................................... 86 Figure 6.32: Energy v/s Years with and without insulation. Source: Author........................................ 87 Figure 6.33: Variation of operational energy with variations in envelope. Source: Author. ................ 88 Figure 7.1: Variation of operational energy with orientation for different built forms. Source: Author. .............................................................................................................................................................. 90 Figure 7.2: Variation of Cumulative energy with time for different envelope options. Source: Author. .............................................................................................................................................................. 92 Figure 7.3: Embodied energy share of building envelope material. Source: Author. ........................... 92 Figure 7.4: : Variation of operational energy with insulation. Source: Author. ................................... 93 Figure 7.5: Variation of operational energy with variations in envelope. Source: Author. .................. 94

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

LIST OF TABLES Table 2.1: Operational energy for dwellings in different climatic zones. Source: (Praseeda, Mani and Venkatrama, 2013)................................................................................................................................ 23 Table 5.1: Embodied energy for enclosure materials in single houses. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf............................................................................. 44 Table 5.2: Building envelope material R-value. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F021.pdf .................................................................................................................................................. 45 Table 5.3: The building envelopes energy. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F021.pdf .................................................................................................................................................. 45 Table 5.4: Operational energies for both the houses. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf............................................................................. 46 Table 5.5: House 1 Life Cycle energy. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf . 46 Table 5.6: House 2 Life Cycle energy. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf 47 Table 5.7: Embodied energy calculation for the dwelling. (Source: Praseeda, Mani and Venkatrama, 2013). .................................................................................................................................................... 49 Table 5.8: Operational energy for dwellings in different climatic zones Source: (Praseeda, Mani and Venkatrama, 2013)................................................................................................................................ 50 Table 6.1: Operational energy values for L shaped plan. Source: Author. ........................................... 57 Table 6.2: Operational energy values for courtyard shaped plan. Source: Author. .............................. 59 Table 6.3: Operational energy values for singly loaded corridor plan. Source: Author. ...................... 60 Table 6.4: Operational energy values for doubly loaded corridor plan. Source: Author. ..................... 62 Table 6.5: Operational energy values for option A. Source: Author. ................................................... 68 Table 6.6: Operational energy values for option B. Source: Author..................................................... 73 Table 6.7: Operational energy values for option C. Source: Author..................................................... 78 Table 6.8: Operational energy values for option D. Source: Author. ................................................... 83 Table 6.9: Operational energy values for varying insulations. Source: Author. ................................... 85 Table 6.10: Operational energy values for different variations in envelope. Source: Author. ............. 88

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

CHAPTER 1: INTRODUCTION The energy consumption in buildings has been a field of study for quite some time, but the focus has always been on the operational phase of the building which includes processes like heating, ventilation, cooling and lighting. There is very little discussion on the energy that is required to construct the building, including the manufacturing and procuring of the materials, as well as their efficiency in the buildingâ€&#x;s envelope. Moreover, in the context of hotels, there is hardly any concern regarding the buildingâ€&#x;s envelope and the choice of greener materials as much of the thought is placed on the aesthetics of the shell only.

Historically, buildings throughout the world have been constructed using locally available materials so as to adapt to the local climate for thermal comfort. The different components of the building like indoor spaces, doors, windows etc. were located and oriented so as to attain maximum climatic advantage. As an example, in traditional Rajasthani architecture, the building envelope was made of materials with high thermal capacity such as mud and stone. Also, the dwellings were clustered together, maximum volume and minimum surface area exposed to the sun was achieved, thereby increasing the thermal mass of the building as a whole. This created a thermal time lag and allowed the heat to reach the building during low night temperatures but not during the day. Another example of wise use of the envelope is the employment of small windows of houses in Manali, Himachal Pradesh so as to minimise any heat losses.

The building envelope has various function like providing security, privacy, comfort and shelter from weather, fire protection as well as provide aesthetics, ventilation and views to the outdoors. The key challenge is to optimise indoor comfort due to the envelope while reduce energy consumption. The energy performance of the building envelope is critical in determining the amount of energy required for other energy loads such as heating, ventilation and cooling. Energy loss through the building envelope is highly variable and depends on many factors, such as building age and type, climate, construction technique, orientation, geographical location and occupant behaviour. According to the United States Department of Energy, 40% of the energy used to heat and cool the average building is lost due to uncontrolled air leakage through the building envelope. Uncontrolled air leakage can also lead to early deterioration of building materials; ice damming, condensation and mold, uneven temperatures and odours leading to occupant discomfort.

1.01 Building Energy Scenario in India The Indian Construction Industry is a rapidly developing sector accounting for 25% of the Gross Domestic Product (GDP) (Indian Buildings Congress, 2008). Rapid urbanisation and income growths have driven the demand for better habitats. The leading surge in Indiaâ€&#x;s building industry comprises

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

the hospitality sector, organised retail and commercial spaces. The housing shortage in India is 2728% which means that there is an urgent demand for residential spaces. Moreover, there is an increase in middle and high income groups, greater use of electrical appliances in all buildings and wider electrification of rural households. Therefore, there are many drivers of growth in energy demand for buildings.

Globally, buildings account for 40% of the total national energy consumption. In 2009, the building sector in India accounted for one third of the total energy consumption (BEE, 2009). According to McKinskey, (2009): •

By 2030, more than 500 million people are expected to live in cities and 70-80% of the

building stock required is yet to be built.

•

By 2020, 22 billion sqm. is to be added and is expected to double by the end of the following

decade.

•

The annual steel and cement consumption will increase six to seven times primarily driven by

construction and infrastructure development.

The consumption of building materials like cement, steel, brick and timber has grown by nearly forty percent or more in the last five years, whereas the use of plastics has shown a tremendous increase of ten times more in the last decade and it is likely to increase more rapidly.(Indian Buildings Congress, 2008).

This indicates that the nation‟s fast growing economy and infrastructure is creating a huge demand for building spaces and subsequently energy also. Without energy efficient buildings, the country‟s energy demand will soon overrun the energy generation capacity leading to acute energy shortages. It is projected that if energy efficiency of buildings in India is not prioritised, the total electricity related emissions from buildings could be more than 390% higher than current levels by 2050 (UNEP 2010).

Since majority of the building stock required for the forthcoming decades has not yet been built, there is huge potential for energy conservation in buildings.

1.02 Energy use in hotels Hotels constitute one of the most energy and resource-intensive branches in building sector as they are operational for 24 hours. Substantial quantities of energy are consumed in providing comfort and services to guests, many of who are accustomed to, and willing to pay for exclusive amenities, treatment and entertainment. The energy efficiency of the many different end-users in hotel facilities is frequently low, and the resulting environmental impacts are, therefore, typically greater than those caused by other types of buildings of similar size. The effects on the environment are caused by the

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

excessive consumption of resources (e.g., water, food, electricity, and fuels), as well as by emissions released to air, water and soil. The large quantities of waste products generated in hotel facilities pose a further significant environmental threat.

The energy use varies substantially between different types of hotels, and is affected by hotel size, class/category, the number of rooms, customer profile (guests visiting for business/on vacation), location (rural/remote or urban), climate zone, as well as by the types of services/activities and amenities provided to guests.

A hotel can be seen as the architectural combination of three distinct zones, all serving distinctly different purposes: 

The guest room area (bedrooms, bathrooms/showers, toilets) - individual spaces, often with extensive glazing, asynchronous utilization and varying energy loads.



The public area (reception hall, lobby, bars, restaurants, meeting rooms, swimming pool, sauna, etc.) - spaces with a high rate of heat exchange with the outdoor environment (high thermal losses) and high internal loads (occupants, appliances/equipment, and lighting).



The service area (kitchens, offices, store rooms, laundry, staff facilities, machine rooms and other technical sections) – energy-intensive areas typically requiring advanced air handling (ventilation, cooling, heating) (Hans De Keulenaer, 2008).

The energy flows occurring in these three areas are usually very different, and need to be handled accordingly.

Past investigations of the energy use in hotels have shown that electricity is the primary source of energy in the hotel industry, while the shares of gas and oil are considerably smaller. The amount of electricity consumed in hotels is thus a good indicator of the overall energy expenditure in this sector.

About 40% of the energy used in a hotel is electricity, 60% comes from natural gas and oil fuels.

These energy bearers are bought in by the hotel. The energy is converted by a number of conversion systems into the most important internal flows of energy, namely heat, cold and electricity. (Hans De Keulenaer, 2008). These energy flows are used for among others the following applications: Heat is used in the form of hot water or in the form of steam. Steam is rarely used in hotels. Hot water is used in the form of central heating and hot tap water. Central heating can be done by radiators in the rooms, or by heating installation in the HVAC units. Gas-fired boilers or cogeneration systems generate the heat.

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

Electricity is used for a wide variety of purposes. The largest electricity consumers in a hotel are lighting, HVAC fans, cooling machines, circulation pumps, some water heating, food service and office equipment.

Cooling is used mainly in HVAC systems, for cooling and drying the ventilation air. Mostly, cooling is produced in the form of ice water. In many cases it is generated centrally by means of compression coolers. In combination with cogeneration, absorption-cooling machines are used to supplement compression coolers.

Energy use in hotels

5%

8% Air conditioning 8%

Illumination 46%

Kitchen/cold storage Water supply/boilers

12%

Laundary Elevators 21%

Figure 1.1: Typical energy end use in a hotel. Source - Energy & Environmental Performance Index for Buildings: Luxury Hotels In India (Bansal and Roy)

1.1 Objectives 

To understand the building envelope in terms of energy consumption in hotels.



To study the materials employed in the building envelope of hotels



To study the embodied energy and operational energy consumption and life cycle assessment of a hotel



To understand the environmental impacts of energy consumption in hotels.

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

1.2 Significance of Study In the hotel industry, sustainability measures are being employed but mostly to the products and services within the building like lighting, HVAC, equipment etc. However, there is very little emphasis on the building‟s envelope as most of the thought is placed on the exterior aesthetics only.

Therefore, this research attempts to create awareness regarding the importance of the envelope in the overall energy consumption of the building.

1.3 Research Methodology 

The research will be based on data collection through primary and secondary sources. The primary case study will start with the assessment of operational energy of a business hotel in 8 different orientations with the help of computer aided simulation on eQUEST software. The same will be done for 3 different options of the same plan by altering the built form.



For the most efficient option, 4 different envelope options will be applied and assessed for embodied, operational and cumulative energy.



The research will further understand the impact of insulation on the best option of envelope and other ways to further reduce the overall energy of the building.

Primary Case Study: Life cycle assessment of the building envelope of a business hotel

Secondary Case Studies: Case studies on LCA and building envelopes

Analysis and simulation Calculations of operational energy of hotel with different options of the built form, envelope and insulation

Conclusion and Recommendation Best possibility of the envelope in terms of energy efficiency Recommendation for designers

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

1.4 Research Questions 

How the building envelope contributes to the energy consumption in a hotel?



How the building envelope‟s embodied energy contributes to the overall global warming potential?



What is the overall impact of embodied and operational energy to the global warming potential?

1.5 Limitations of Research The research has the following limitations: 

The research only focuses the guest room block of the business hotel as this accounts for the majority of the building.



The research only focuses in the exterior shell, i.e. the building‟s envelope



The human energy is taken as zero for all calculation purposes

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

CHAPTER 2: LITERATURE REVIEW Till date, the primary focus of majority of researchers has been on the energy used during the operational phase of the building. However, an important factor that has been neglected is the embodied energy of construction materials. This research is inspired by the need to incorporate energy efficient and smart materials into the design and operation of the building‟s envelope and to reinvent indoor thermal comfort. The following chapter provides an overview of the research related to building envelope and energy consumption in buildings.

2.1 Building Envelope Many authors define building envelope as the physical interface between the indoor and the outdoor environment. Cleveland and Morris (2009) created a good working definition of building envelope as “the collective term for all the components of a building that enclose its conditioned space and separate the conditioned spaces from the unconditioned spaces”. Grondzik, Kwok, Stein, & Reynolds, (2011) define building envelope as “a three dimensional transition space-a theatre where the interaction between the outdoor forces and indoor conditions occur under the command of materials and geometries.” For the purpose of this research, the building envelope or skin is considered to be the climatic barrier that separates the indoor and outdoor environments.

The basic components of a building envelope include walls, roofs, floors, doors and windows and foundation. Norberg Schulz(1965) suggests that a component can be more fundamentally thought in terms of its design intent relative to the exchange of energies: as a filter, connector, barrier or switch.

The building envelope is the initial and primary means to conserve energy and control occupant comfort. With attention from the designer, the envelope can maximize occupant comfort, including thermal control, air quality, daylight, humidity, acoustics, and security; while minimizing running costs through the use of solar, wind, and daily temperature variations.

For an effective energy-efficient envelope, design conditions for the indoor and outdoor environments must be known in order to understand the loads the envelope will endure. This requires a clear definition of indoor comfort as a benchmark for the design process. With energy efficiency as a driving force for future building design, the building envelope is the primary element for reducing whole building energy use, encouraging the building designer to design the envelope to meet as many energy loads and comfort requirements as possible, and allowing any unmet loads to be handled by a smaller sized HVAC system (Torcellini, et al., 2006).

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

2.2 Embodied Energy According to Indian Buildings Congress (2008), “embodied energy is measured as a quantity of nonrenewable energy per unit of the building material, component or system. The embodied energy per unit mass of materials used in buildings varies enormously, from about two giga joules per ton for concrete to hundreds of joules per ton for aluminium.�

Embodied energy includes energy consumed by all the processes associated with the construction of a building - from the acquisition of materials and equipment, the transport of the materials and the administrative functions. It is a significant component of the lifecycle impact of a building(Indian Buildings Congress, 2008).

Embodied energy is divided into two major phases which are the Initial embodied energy and Recurring embodied energy. Initial embodied energy is non-renewable energy consumed in the process from the acquisition of raw materials to the construction of the building. For example, a steel window frame will have the initial embodied energy that is derived from the mining of the ore, its melting and processing, the transportation of the steel to the window manufacturing plant, the manufacturing of the window frame and its transport to the building site. Initial embodied energy is influenced by the source and type of building materials and the nature of the building.

Recurring embodied energy is non-renewable energy consumed to maintain, repair, restore, refurbish or replace materials, components or systems during the buildingâ€&#x;s life span For example, a window frame that is not sufficiently protected from rust might have to be replaced, or painted. Recurring embodied energy is influenced by the durability and maintenance of building materials, systems and components installed in the building, and the life span of the building. As the life span of a building increases, the operating energy significantly increases and the initial embodied energy of the building becomes insignificant in comparison.

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2% 1%

FOUNDATION AND BASEMENT1st Qtr

5% 9%

27%

EXTERNAL AND INTERNAL WALLS CEILINGS, STAIRS AND FLOORS ROOF

19% HEATING SYSTEM ELECTRICAL INSTALLATION

37%

SANITARY INSTALLATION

Figure 2.1: Share of different components in total embodied energy. Source: (Indian Buildings Congress, 2008).

Figure 2.2: Comparison of Initial to Recurring Embodied Energy for Wood Structure Building Over a 100-Year Lifespan. Source: (Cole and Kernan, 1996).

Modern building materials like concrete, concrete-blocks, glazed bricks, steel, aluminium tend to contain substantially more embodied energy than traditional building materials. According to a research conducted by Venkatrama Reddy(2009), contemporary buildings which use RCC framed structures with infill walls and glass and aluminium for openings have their embodied energy in the range of 5-10 GJ/m2,whereas the embodied energy of load-bearing masonry residential buildings lies in the range of 3-5 GJ/m2. He also concluded that the energy consumed by a building composed of Stabilized Mud Blocks (SMB) was about 50% less than any conventional RCC or load bearing masonry building. Hence, the use of alternative building technologies results in considerable amount of reduction in the embodied energy of a building. Also, the studies of Buchanan and Honey, Suzuki, Debnath, Venkatrama Reddy and Jagdish emphasize a shift in construction from conventional

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materials like brick, steel and concrete to low-energy alternative materials in order to cut down energy costs and reduce carbon emissions.

Development Alternatives, a Delhi based organization has been involved in research and development of building materials that utilise industrial wastes and have low embodied energy like micro concrete roofing tiles (MCR), paving blocks, stabilised concrete earth blocks, prefabricated roofing elements, precast doors and window frames. The MCR tiles prove to be a better material than conventional roofing due to its cost effectiveness, structural strength and lowest embodied energy. The DA group has further worked on alternative materials like Stabilised Compressed Earth Blocks, ferro cement roofing channels, precast RCC planks and joists, precast arch panels and RCC concrete door and window frames.

2.2.1 Importance of Embodied Energy Until recently, the emphasis of energy conservation was mainly on the operational energy of a building, while embodied energy was assumed to be relatively insignificant .However; current research has invalidated this assumption and found that embodied energy accounts for a significant proportion of total life cycle energy. Academic studies have illustrated that embodied energy accounts for the majority of a buildingâ€&#x;s energy footprint for approximately the first 15-20 years of a buildingâ€&#x;s life-cycle.

Figure 2.3 Embodied and Operational Energy Relationship. (Source: Nancy W. Stauffer, MIT Energy Initiative,2009)

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The envelope and structure alone account for approximately 50% of a buildingâ€&#x;s total embodied energy, the carbon footprint of buildings can be reduced by selecting existing buildings for interior build-outs, renovations, or adaptive reuse projects. Interior finishes account for approximately 13% of a buildingâ€&#x;s embodied energy, so adaptive reuse or interior build-out projects have an overall smaller energy footprint that new construction. However, selecting a renovation/reuse project is not enough; the quantity and type of materials used in the project is also important. For the most positive impact, we need to select materials with lower embodied energy, higher durability, lower levels of toxicity, and overall positive life-cycle impacts.

2.3 Operational Energy Operational energy can be defined as the energy consumed by the building mechanical and electrical systems for heating, cooling, appliances and lighting (Syed, 2012). It is the energy consumed during the operational phase of the building. Operational energy of a building is almost three to four times the embodied energy over the life cycle of a building. As the building ages, the embodied energy remains the same whereas the operating energy rises (Syed, 2012).

According to a research conducted by Praseeda, Mani and Venkatrama Reddy in 2013, operational energy of three different wall materials; rubble stone masonry, burnt clay brick masonry and stabilized soil blocks, for three different thermal comfort models in two different climate zones was assessed using building simulation model. OE for the dwelling included energy for thermal comfort and lighting. Total operational energy (sum of thermal comfort energy and lighting energy) of the dwelling for different scenarios was then expressed in terms of GJ/m2/year. Table 1 summarizes the seasonal OE estimates for the traditional dwelling based on the ASHRAE model, for various wall configurations and climatic zones. Energy for indoor lighting was estimated at 1706.31 kWh/year for all the cases.

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Table 2.1: Operational energy for dwellings in different climatic zones. Source: (Praseeda, Mani and Venkatrama, 2013)

Figure 2.4: Comparison of annual air-conditioning energy for the traditional

dwelling with varying wall configurations and climatic zones, with ASHRAE 55 as the reference model. Source: (Praseeda, Mani and Venkatrama, 2013)

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From the results, it is clear that there is negligible variation in OE(less than 1kWh/m2 per year) for warm-humid and moderate climate zone. Similarly, for identical wall configurations also, there is negligible variation in the OE for the two wall systems. However, in case of hot and dry zone, there is significant variation of OE( nearly 4kWh/m2 per year) for the different wall systems as well as identical wall systems when compared to the other two climatic zones.

2.3 Life Cycle Assessment In ISO 14040, Life Cycle Assessment(LCA) is defined as the “compilation and evaluation of the inputs, outputs and potential environmental impacts of a product system throughout its life cycle�.

Thus, LCA is a tool for the analysis of the environmental impacts materials have throughout their life cycle. The LCA involves examining the product from the extraction phase for the manufacturing process to the production and use of item, to its final disposal(Kulkarni and Ramachandra, 2009).

Figure 2.5: Stages of Life Cycle Assessment. Source: (Blanchard & Reppe, 1998) (Hsu, 2009) (Kulkarni & Ramachandra, 2006) (Punmia, Jain, & Jain, 2005), (2009)

Performing life cycle assessments of construction materials is not a new concept. Because materials such as concrete and steel are used in such massive quantities, their environmental impacts have long been a subject of interest.

In a research conducted by Steven Blanchard and Peter Reppe, the life-cycle energy, greenhouse gas emissions, and costs of a contemporary 228 m2 U.S. residential home in Michigan (the standard home, or SH) were evaluated to study opportunities for conserving energy throughout pre-use (materials production and construction), use (including maintenance and improvement), and demolition phases.

Home construction and maintenance materials and appliances were inventoried totalling 306 metric tons. The use phase accounted for 91% of the total life-cycle energy consumption over a 50- year home life. A functionally equivalent energy-efficient house (EEH) was modelled that incorporated 11 energy efficiency strategies. These strategies led to a dramatic reduction in the EEH total life-cycle energy; 6,400 GJ for the EEH compared to 16,000 GJ for the SH. For energy-efficient homes, embodied energy of materials is important; pre-use energy accounted for 26% of life-cycle energy.

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EEH was modelled for greater energy efficiency to determine by what degree environmental impacts could be reduced, and at what incremental cost. It was also modelled to have the same floor plan and internal dimensions as the SH. The guiding principle in the design of EEH was to minimize life cycle energy. 91% of SH life cycle energy consumption occurs in the use-phase. Thus, EEH design changes focused on minimizing use phase energy. Measures to reduce the material fabrication/construction (pre-use phase) energy by choosing materials with lower embodied energy were also taken.

A research conducted by Eaton and Amato(1998) at the Steel Construction Institute of United Kingdom produced a comprehensive analysis of Steel and Concrete Office Buildings. The study focused on the construction and operational phases of the structural systems, with attention given to the possibility of recycling the materials afterwards. The research showed that although concrete frames have overall higher enbodied energy and CO2 emissions, the difference swere insignificant.

Also, the total life cycle energy including use was 10-15 times higher than the initial embodied enrgy fot these buildings.

Kofoworola and Gheewala conducted a recently constructed office building in Bangkok. Instead of performing a traditional LCA, the researchers completed a life cycle energy analysis (LCEA), which focuses purely on energy use rather than emissions and other aspects of a full LCA model. The energy consumption according to phases in the buildingâ€&#x;s life cycle is represented below:

Figure 2.6: Energy consumption due to different phases in a buildings life cycle. Source: Kofoworola and Gheewala

Total embodied energy for the building was found to be 375 terajoules, corresponding to approximately 6.8 GJ/m2. Approximately 78% of this energy originated from the concrete and steel building materials and this embodied energy corresponded to about 15% of the buildingâ€&#x;s operational energy over its projected lifetime. The embodied energy values computed in the study closely matched those of existing governmental data, and previous energy studies estimate a buildingâ€&#x;s embodied energy per square meter as ranging from 3.4-19.0 GJ/m2.The researchers attributed the

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buildingâ€&#x;s high embodied energy to the large quantities of material required to construct a reinforced concrete frame. Although it is not stated explicitly, a steel-framed structure would presumably use less material and have a lower embodied energy.

Figure 2.7: Breakdown of embodied energy due to different materials. Source: Kofoworola and Gheewala

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CHAPTER 3: TYPES

OF

BUILDING

ENVELOPE

TREATMENTS 3.1 Masonry wall systems Masonry has been used in building since the dawn of construction. In masonry construction, different units are laid in a course and bonded together with the help of site mixed mortar or mud. Masonry is commonly used in the building envelope for walls, retaining walls and foundations. The commonly used materials as units for masonry are:

3.1.1 Brick Bricks are typically formed of soft clay and moulded into the required shape of predetermined in the manufacturing plant. Brick units are then heated in a kiln to a temperature of 1100 to 1200 Fahrenheit degrees in order create the structural properties of the units. Generally, bricks used in India are of the size 230X115X75 mm.

3.1.2 Stone Stone masonry is a traditional form of construction that has been practiced for centuries throughout the world. Stone was used as a part of the envelope where massive loads had to rest on load bearing walls. Stone masonry utilizing dressed stones is known as ashlar masonry, whereas masonry using irregularly shaped stones is known as rubble masonry. Today, stones are an integral building material for flooring, external as well as internal wall cladding.

3.1.3 Concrete Blocks Concrete blocks or concrete masonry units (CMUs) are manufactured by mixing Portland cement and aggregate under controlled conditions. Concrete blocks are usually larger in size than ordinary bricks and have lower water absorption rats than bricks. They often are used as the structural core for veneered brick masonry, or are used alone for the walls of factories, garages and other industrial-style buildings where such appearance is acceptable.

3.2 Cavity wall In a cavity wall system, two vertical layers of masonry are separated by an air space called as cavity.

The masonry is an absorbent material and hence will absorb any rainwater or moisture into the wall.

The cavity acts as a way to drain the water out through weep holes at the base of the wall system or above windows.

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The cavity should start near ground level and terminate near eaves level in case of sloping roof or near coping in case of flat roof with parapet wall. The cavity should preferably start 15 cm below the damp-proof course level. This has the advantage of draining any condensed moisture below the level of damp-proof course. Similarly, to prevent infiltration of moisture, the bottom of cavity should lie at least 15 cm above the outside ground level. The damp-proof course for the two leaves is laid separately, although at the same level. This is necessary to continue the cavity below damp-proof course. The cavity is kept fully ventilated by providing air bricks in the external wall immediately above damp-proof course. Cavity wall has many benefits over a simple masonry wall envelope: •

The possibility of moisture penetration is greatly reduced as there is no contact between the

inner and outer layers of the wall expect the wall ties •

Cavity walls provide good heat insulation as air is a non-conductor of heat. It has been

establishes that cavity walls of the same cross section as a solid wall less the cavity thickness provides 25 per cent more heat insulation over the solid wall.

•

They also offer good sound insulation (Punmia and Jain, 1993)

Figure 3.1: Cavity wall section. Source: http://www.thewarmergroup.co.uk/insulation/homeowners/cavity-wallinsulation#.VCUH-vQW39U

3.3 Jali A jali is a form of envelope system consisting of perforated stone or latticed scree. It is often ornamented in various patterns through the use of calligraphy and geometry. This type of façade is a common element of Indian architecture, Indo-Islamic Architecture and Islamic Architecture. Jali

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screens are constructed even today. Partial mechanization of the process through the use of drilling machines has made the process more time efficient.

The jali screen acts as a mediator within the building envelope, regulating the external layer by blocking any direct sunlight and reducing the Thermal Transmittance. The Jali acts a tool for selective shading by protection from direct sunlight in the summers and opening up to the sun in winters. The jalis also ensure a constant flow of breeze into the interior, allowing the occupant comfort in the hot humid climate.(Batool, 2014)

Figure 3.4: Jali at Sidi Saiyyed Mosque.

Source: http://en.wikipedia.org/wiki/Sidi_Sai yyed_Mosque

Figure 3.3: Godrej Green Business Centre in Hyderabad with Jali facade.

Source: http://www.infrawindow.com/green -spaces/godrej-green-businesscentre-hyderabad_5/perforatedwalls_14

Figure 3.2: Jali at Tomb of Salim Chisti, Fatehpur Sikri, Agra.

Source: http://en.wikipedia.org/wiki/ Tomb_of_Salim_Chishti

3.4 Curtain wall Curtain wall is a type of an envelope system consisting of thin frames of aluminium, steel or any other resilient material containing in fills of glass panels. Other materials may be also be incorporated between the glazing units, including brick veneer, precast concrete, metal panels, and thin stone.

These frames called as mullions support the panel on four sides. The framing is attached to the buildingâ€&#x;s structure with the help of brackets but does not carry the floor and roof loads. Curtain walls became popular in the early 1900s after the industrial revolution and the availability of factory made glass and aluminium. This system is generally adopted in office, commercial and retail buildings.

Based on the process of fabrication, curtain wall can be classified as stick systems or unitized systems. In a stick system, the glazing panels and the mullions are assembled on site whereas in a unitized system, the panels along with the frames are assembled in factory and the units are installed on site.

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Thermal loads are induced in a curtain wall system because aluminium has a relatively high coefficient of thermal expansion. This means that over the span of a couple of floors, the curtain wall will expand and contract some distance, relative to its length and the temperature differential. This expansion and contraction is accounted for by cutting horizontal mullions slightly short and allowing a space between the horizontal and vertical mullions. In unitized curtain wall, a gap is left between units, which are sealed from air and water penetration by wiper gaskets.

Figure 3.5: A typical curtain wall section.

Source: http://www.aluk.co.uk/sl52curtain-walling.php

3.5 Double-skin Envelope The double-skin envelope or double-skin faรงade system comprises of two skins placed in such a way that air flows in the intermediate cavity. The cavity may be naturally or mechanically ventilated. The width of the cavity can vary between 200 mm to more than 2m. This width influence the way that the faรงade is maintained.

One of the advantages of the Double Skin Faรงade System is the intermediate placed shading devices combined with ventilation inside the cavity. As the solar radiation is being absorbed by the shading devices the temperature inside the cavity is increased. Due to the stack effect approximately 25% of this heat can be removed by natural air circulation. Apart from that, the Double Skin Faรงade also reduces heat losses since inside the cavity the air velocity is reduced and the temperature is higher.

The higher temperatures inside the cavity during heating periods lead to increased temperatures close to the windows, and as a result improved thermal comfort for the occupants.

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Figure 3.6: Typical Double-Skin Facade configuration.

Source: http://www.fenestrapro.com/seeing-double-part-i-the-concept-of-a-double-skinfacade-2/

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CHAPTER 4: CASE STUDIES OF BUILDING ENVELOPES 4.1 Traditional Building Envelopes: Havelis of Shekhawati Shekhawati is a semi-arid region located in the north-eastern part of Rajasthan and is famous mostly for its traditional Havelis. The case study focuses on havelis most of which were built 100-200 years back but still portray an example of envelope solutions to the climatic conditions even today. It is surprising to note that most of the passive design features recommended by designers and energy conservationists are already incorporated in the envelopes of these old havelis. Hence, these features present before us the most suitable passive design measures and construction methods to take care of the increasing energy demands today.

Figure 4.1: Facade treatment in a typical Haveli (Source:http://www.wackywanderlust.com/2014/01/ open-art-gallery-of-shekhawati-explores.html)

Case Study The case study focuses on a small scale haveli in Shekhawati that has two courtyards as the trend there is of having minimum two courtyards.

Figure 4.2: Ground and First Floor plans of http://www.unige.ch/cuepe/html/plea2006/Vol1/PLEA2006_PAPER978.pdf)

the

haveli

(Source:

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Passive design strategies in the envelope The building envelope is made heavy to store larger amount of heat due to large heat capacities and creates a greater time lag. This helps in keeping the inside space cool during the daytime when temperatures are high outside. The general specifications of the envelope are: Walls:

450 mm thick walls made of locally availably stone plastered with lime

Roofs:

The roof is made of 450 mm thick stone with lime mortar on it. The roofing plaster is composed of lime, jiggery and hessian. This is followed by a layer of inverted earthen pots for insulation with a layer of lime mortar finished with reflective broken pieces of porcelain which reflects most of the sunlight.

Openings: The openings are small with thick shutters, jail screens and jharokhas to block the dry and dusty winds during the day and allow a draft of air inside. All the openings are shaded with perforate stone screens or jharokhas which allow passage of cool air by venture effect (Fig. 3)

Figure 4.4: The Venturi Effect through the hole of a Jali

Figure 4.3: A typical jharokhas in a haveli.

Source: http://www.photonicyatra.com/Destin ations/India-Rajasthan-Jodhpur

Construction Materials: The materials used in the construction of the envelope are mainly stone and lime mortar which have long life and hence least recurring embodied energy Lime mortar allowed keeping lower temperatures inside the building. Stone helped in creating time lag due to high thermal capacities.

Findings 

The inside of the haveli created a comfortable environment even though the outside conditions were unsuitable.



The high thermal mass of the walls and roof created a comfortable indoor environment as it led to a reduction in indoor temperature.

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

The haveli achieved natural air flow through the jail without the aid of any mechanical ventilation.



The materials used are locally available as well as long lasting and durable. Hence, the envelope has an overall low embodied energy.

4.2 Traditional Building Envelopes: Hawa Mahal The Hawa Mahal or the „Palace of the winds‟ located in Jaipur was built by Maharaja Sawai Pratap Singh, and designed by Lal Chand Ustad in 1799. It was built as an extension to the women‟s chambers to enable the women of the royal household to watch the everyday life and royal processions in the city without being seen by others.

Design Features in the Envelope The entire structure is built of red and pink sandstone which is the locally available material. The palace exhibits a unique five storey façade which is similar to a honeycomb of the beehive with its 953 small windows called jharokhas that are decorated with complex lattice work.

The front elevation of the façade facing the main road is a veritable mass of semi-octagonal bays, which gives the monument its unique facade. Each bay consists of small windows which are decorated with jali work and also stained glass.

Figure 4.6: Jharokhas on the facade.

Source: http://theyoungbigmouth.com/2014/ 04/05/hawa-mahal-jaipur/

Figure 4.5:The front elevation of the palace.

Source: http://theyoungbigmouth.com/2014/04/0 5/hawa-mahal-jaipur/

Findings: 

The most striking feature of the envelope is it cooling effect which is achieved by natural airflow through small openings in the jali through venture effect. One can actually feel cool breezes of air blowing when inside the palace. The jaali also helps to cast shadows inside the palace keeping the indoor environment cool

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

The stained glass in the openings also helped in shading by cutting the overall solar gain. Also the low percentage of openings to the external façade minimised heat gain.

Figure 4.7: Stained glass openings.

Source: http://theyoungbigmouth.com/2014/04/ 05/hawa-mahal-jaipur/



The material used in the walls, i.e. red sandstone has a high thermal mass which increases the time lag of the heat gain which kept the indoors cooler during the day and warm during the nights.

4.3 Modern Building Envelope: Terry Thomas Office building The Terry Thomas Office Building is a five floor building located in Seattle. The building offers 3500 m2 of office space on four floors and 280 m2 of retail and restaurant space on the ground floor. There were many driving factors in the design of the built mass and the envelope. The primary project goal aimed to create an environment that enhances occupant well-being by incorporating daylighting, natural ventilation and individual control of the indoor environment.

To take advantage of daylighting and cross-ventilation throughout all of the occupied spaces, the design team proposed a central courtyard and limited the depth of the floor plate to 12 meters. A detailed energy simulation of the building was conducted to determine the range of strategies to be employed to prevent the indoor spaces from overheating.

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Figure 4.8: South courtyard elevation. http://escholarship.org/uc/item/4vq936rc#page-57

Source:

Design Strategies in the Envelope: Roof: The roof is made of steel decking with gypsum sheathing and an overall reflectivity of 95 to reflect most of the heat falling on the roof.

Walls: The walls are made up of metal framing, gypsum sheathing with batt insulation and corrugated metal cladding Windows: The windows were designed so as to maximize views and daylighting and minimize solar gain. The effect of natural ventilation as a means of passive cooling was modelled using thermal analysis early in the design process. This determined the required number of operable windows and the areas that would need shading. Tinted glasses have been used in all windows to minimize solar gain along with overhangs on the east and west elevations.

Shading: The most unique feature of the faรงade is its shading design. With the help of shading, the building eliminates the entire need for mechanical cooling during summer months. Thermal modelling was conducted on each floor of the building for each orientation to determine the optimum shading strategy to minimize solar gain.

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A series of automated louvres are installed near the ceiling of each floor all along the perimeter of the building which together with operable windows optimizes natural ventilation. The louvers are controlled by a thermostat and open according to the outside temperatures.

The second shading strategy which the building employs is the use of automated venetian blinds which offset the windows. The northeast, some east and west windows, and the south façade facing the courtyard use dynamic external venetian blinds. A rooftop sensor measures the light level and sun angle, and automatically adjusts the blinds as necessary.

Figure 64.9: Fixed exterior overhangs.

Fixed exterior overhangs Source: http://escholarship.org/uc/item/4vq9 36rc#page-57

Figure 4.10: Automated exterior venetian blinds.

Source: http://escholarship.org/uc/item/4vq93 6rc#page-57

Findings: 

The building completely eliminates the requirement of mechanical cooling through the employment of mechanical shading and operable windows in the envelope which cuts down the operational energy significantly.



However, the use of energy intensive materials like steel, aluminium and glass throughout the envelope increase the embodied energy of the building. Also, automated louvers and venetian blinds require high maintenance and hence lead to increase in the overall embodied energy.



The use of automated louvres, venetian blinds and operable windows cut down cooling load significantly, however, the building has been reported to have significant heat losses during the winter months (Zelenay, Perepelitza and Lehrer, 2011). This could have been achieved by reducing the glazing percentage or using spandrel or insulated wall in the lower portions of the windows.

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4.4 Modern Building Envelope: Transport Corporation of India, Gurgaon The transport corporation of India located in Gurgaon is a three storey office building designed by Ashok B. Lall Architects. Its basic design strategy is inspired by the traditional inward-looking haveli plan with a central courtyard. The orientation of all the interior spaces is towards the central courtyard.

Figure 4.11: TCIL building, Gurgaon. Source: http://high-performancebuildings.org/tcil.php

Design Strategies in the Envelope: Built Form: The building has a compact rectangular form and minimum height above ground to limit exposure to the external conditions. The building has a North East-South West orientation to cut down radiation which results in lesser heat gains and reduced the overall air-conditioning requirement and hence saves energy. Proper orientation also helps in receiving natural light and ventilation.

Walls: The building adopts a heavy mass construction strategy. The 230mm thick brick wall is insulated by a 25mm thick polyurethane foam layer which is protected by red stone slab cladding.

Figure 4.12: Wall Section. Source: http://highperformancebuildings.org/tcil.php

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Roof: The roof insulation is 35 mm thick and has a reflective glazed tile paving cover to minimise the temperature on the roof surface and helps in reducing the cooling load.

Openings: The building employs two different sets of openings or windows for two separate functions. Small peep windows are installed at the seating height to provide for cross ventilation and outdoor views.

These windows are recessed inside the walls due to which the external reveal acts as a shading device by cutting out mid-summer sun. Larger windows are installed at the ceiling level to distribute glare free light across the office floor. These windows house adjustable venetian blinds in a double-window sandwich. The blinds are to be adjusted seasonally. The overall glazing percentage is minimised to 18% of the external wall area to reduce solar heat gain (Figure 9).

Figure 4.13: Arrangement of openings.

Souce: http://highperformancebuildings.org/tcil.php

The openings however towards the courtyard are large to achieve greater transparency as the courtyard is the cooler part of the building.

Figure 4.14: Larger windows facing the courtyard. Source: http://highperformancebuildin gs.org/tcil.php

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Findings: 

 



The building has a North East-South West orientation to cut down radiation which results in lesser heat gains and reduced the overall air-conditioning requirement and hence saves energy.

The high thermal mass of the wall as well as added insulation helps to cut down annual energy consumption significantly.

The stone used for cladding is undressed split red Agra sandstone which is near to Delhi and hence has a low embodied energy. Also, the stone has a long lifespan and is maintenance free.

Glass and aluminium which are the major contributors to embodied energy have been kept to the minimum possible. The building hence, has an overall low embodied energy.

All work spaces receive adequate daylight. The maximum distance of a workstation from the daylight source is 5 meters. The high windows on the external walls are designed to throw daylight deep into the office space. This is varied seasonally by adjusting venetian blinds installed in the window sandwich to control glare and to modulate distribution. On the courtyard side fabric screens would be stretched over the structural frame to respond to each season. This greatly reduces the annual electrical consumption for lighting as the working hours are generally limited to the daylight hours.

4.1.4 Combination of modern and traditional practices in envelope: India International Centre, New Delhi The India International Centre is a non-government institutional building located on Lodhi Road, New Delhi. It is a 4.76 acre complex consisting of a library, auditorium, restaurant, lounge, offices, hostels and guest rooms. The façade of the residential wing was given a curved form which corresponds to the curving paths and walkways in the adjacent Lodi gardens. The building employs a combination of modern and traditional passive techniques in the envelope. All observations were recorded by the author through a site visit as well as discussion with the assistant engineer.

Figure 4.15: The IIC complex.

Source: http://www.iicdelhi.nic.in/Home.aspx?TypeID=1030

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Design Strategies in the Envelope: Roof: The roof slab is made up of RCC slab with APP water proofing and china mosaic tiles as finish. Place, where curved roof is given, it has been painted with silver paint to reflect most of the sunlight.

Figure 4.16: China Mosaic tiles for roof finish. Source: Author

Walls: The walls are made up of hollow core concrete blocks as well as rugged quartzite stone which was locally sourced.

Figure 4.17: : Rugged quartzite stone wall: Source: Author

Figure 4.18: Hollow core concrete blocks used for external wall. Source: Author

Windows:

Windows are made up of clear glass and aluminium framing throughout. The sizes are large so as to maximize daylighting. In the restaurant wing, wooden wool has been used over windows for thermal and acoustic insulation.

Figure 4.19: Large windows with wooden wool panels. Source: Author

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Shading: The most recognisable feature of the facade of the building the use of jali screen throughout the office and guest room wing. It is made up of fire clay bricks and was inspired from the use of jalis in traditional Mughal architecture.

Figure 4.20: : Use of jali screen throughout the guestroom facade. Source: Author

Findings:  



The use of china mosaic tiles and silver paint as roof finishes reflects most of the sunlight falling on the roof thereby cooling the indoor environment.

The materials used in the wall were locally sourced hence the building skin has a low embodied energy. Also, quartzite stone used in walls has a life span of over 100 years and is maintenance free. Hence, the overall embodied energy of the building is significantly reduced.

The jali screen used in the façade casts shadows which cuts of most of the heat through sunlight, and at the same time allows for daylight. According to the discussion with the assistant engineer, the jali screen had helped to reduce the cooling load in the building quite significantly. Also, the jali screen had undergone a complete replacement only once in its life of 54 years. Hence, it has an overall low embodied energy.

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CHAPTER 5: SECONDARY CASE STUDIES 5.1 Case Study 1: Embodied Energy of Building Envelopes and its Influence on Cooling Load in Typical Indonesian Middle Class Houses This study was carried out by Agya Utama and Shabbir H. Gheewala at The Joint Graduate School of Energy and Environment, King Mongkut‟s University of Technology Thonburi, Bangkok, Thailand for the 2nd Joint International Conference on “Sustainable Energy and Environment (SEE 2006). All the contents of the summary have been taken up from the official report published by King Mongkut‟s University of Technology Thonburi.

Case Study Selection: For the purpose of the study, middle class residential houses were used; the typical materials that are currently used have been chosen along with typical floor area and occupancy rate. The studied houses are air conditioned and having similar occupant behaviours.

The house selected was a single house type 55m2 in area with two rooms and one living room and has a typical gable roof. The air conditioned room has an average volume of 21 m3, is used by three occupants and has a life span of 50 years.

For calculating the operational energy usage, two houses- House 1 and House 2 with different materials in the envelope were selected in Semerang city. House 1 uses concrete block as its walls material, and concrete roof as its roof enclosure. On the other hand, the House 2 uses bricks as main component of its walls and clay tile roof as roof enclosure. Both houses use the same material for roof frame, ceiling and window glass; namely steel, gypsum and clear glass, respectively.

Methodology:

Selection of Standard House

Life Cycle analysis for both the envelopes

Defining two types of different envelopes

Calculation of Embodied energy for the two types

Calculation of Operational Energy for the two types

Conclusion

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Embodied Energy Calculation: Table 1 presents the embodied energy of building materials for typical middle class residential houses in Semarang city. The study reported that more than 75% houses in Semarang, chose concrete roof as their main material for roof enclosure, only less than 25% chose the clay tile roof. This is due to the economic considerations; the concrete roofs work out to be cheaper than the clay ones.

The R-values of the typical envelopes material in Semarang are presented in Table 2. The R-value of clay is much higher than concrete leading to a higher overall value for the roof. It is thus anticipated that the House 2 will have a lower cooling requirement, and consequently lower life-cycle energy, than House 1. This issue is analysed further in the later sections along with quantitative results.

Table 5.1: Embodied energy for enclosure materials in single houses. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf

Material Common Steel Gypsum (3 mm) Single glass (clear 2 mm) Aluminium frame (1 mm) Mold (m2) Cement Sand House 1 Concrete roof (2 mm) (18 pcs/m2) Concrete block (100 mm) (24 pcs/m2)

Embodied energy 32.54 MJ/kg [1] 2.69 MJ/kg 13 MJ/kg [6] 232 MJ/kg 3.361 MJ/kg 0.6 MJ/kg

0.817 MJ/kg 0.762 MJ/kg 16.41 MJ/m2

Mold (1 PC : 5 sand) House 2 Clay roof (2 mm) (18 pcs/m2) Bricks wall (100 mm) (60 pcs/m2) Mold (1 PC : 5 sand)

0.26 MJ/kg 1.3 MJ/kg 29.61 MJ/m2

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Table 5.2: Building envelope material R-value. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf

House 1 Concrete (2 mm) Dead air space Gypsum (3 mm) Total R-value for roof Concrete block (10 mm) Clear glass

Rvalue 0.3 1.01 0.58 1.89 1.11 0.22

House 2

R-value

Clay (2 mm) Dead air space Gypsum (3 mm) Total R-value for roof Bricks (10 mm) Clear glass

2.39 1.01 0.58 3.98 1.90 0.22

The materials included in the envelopes of the two houses are concrete and clay roof, steel frame, gypsum ceiling, concrete block and bricks walls, aluminium windows frame and clear glass. The initial embodied energy of the above materials has been studied.

Table 3 shows the embodied energy of the different materials employed in the envelope of the two houses. It also shows the energy used during construction process which is less than 0.5% for both houses. The total embodied energy for House 1 works out to a little over 50,000 MJ and is considerably higher than for House 2 which is only about 43,700 MJ. From the Table 3, it can be seen that the biggest contributor for the first house is the initial energy for concrete roof which is much higher than the clay roof in House 2. The high energy of concrete roof is due to the high percentage of the cement ingredients. Moreover the biggest contributor for the second house is coming from bricks walls which accounted almost 17,000 MJ. Table 5.3: The building envelopes energy. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf

Material

Volume/mass/ area

Energy per unit

Energy [MJ]

Common Steel Gypsum (3 mm) Single glass (clear 2 mm) Aluminum frame (1 x 5)

House 1 Concrete roof (2 mm) (18 pcs/m2) concrete block (100 mm) (24 pcs/m2) Walls mold House 2 Clay roof (2 mm) (18 pcs/m2) Bricks wall (100 mm) (60 pcs/m2) Walls mold

482.78 kg 55 m24.8 m20.00432 m3

55 m290 m290 m2 55 m290 m290 m2

32.54 MJ/kg 21.60 MJ/m2 671 MJ/m2 353,104 MJ/m3 14.54 MJ/pcs 6.49 MJ/pcs 0.13 MJ/m2 5.19 MJ/pcs 3.13 MJ/pcs 0.23 MJ/m2

Constructio n [MJ]

15,709.66 1,188.00 3,220.80 1,525.41 14,394.60 14,018.40 11.70 5,135.13 16,902.00

20.70

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

Operational Energy Calculation: The operational energy result is based on the cooling load temperature difference calculation for the building envelopes of the two different houses. The theoretical calculation for cooling load was divided into three categories, first is the latent load, second is the internal load (appliances) and third is the perimeter load (load influenced by its enclosure).

Both the houses have the same occupancy rate and occupant behaviour, as well as the number of occupants staying in the air conditioned rooms. The operational energy found out is given in Table 4: Table 5.4: Operational energies for http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf

Operational energy

both

House 1 [MJ/year] [MJ/m2/y ear] 23,638.8 429.80

the

houses.

Source:

House 2 [MJ/year] [MJ/m2/ye ar] 17,728.8 322.34

Life-cycle energy: The Life cycle energies for the two houses are calculated by adding the initial embodied, recurrent embodied and operational energies. The energy values for periods of 30 and 50 years for the two houses are shown in table 5 and 6 respectively:

Table 5.5: House 1 Life Cycle energy. Source: http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf

Year s 30 50

Emergy [MJ] 43,701.70 43,701.70

Replace ment [MJ] 5,135.13

Operatio nal [MJ/year] 17,728.80 17,728.80

Total [MJ] 575,565.70 935,276.83

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Table 5.6: House 2 Life Cycle http://www.jgsee.kmutt.ac.th/see1/cd/file/F-021.pdf

Year s 30 50

Emergy [MJ] 50,068.

57 50,068.

57

Replacem ent [MJ] -

Operatio nal [MJ/year] 23,638.80 23,638.80

energy.

Source:

Total [MJ] 759,232.5 7 1,232,008.

57

Conclusion: On studying the two houses, it showed that the concrete house has a higher embodied energy and also consumes more energy during its operational phase. This is due to the higher R-value of clay roof which leads to a reduced cooling requirement (air-conditioning) and consequently lower life-cycle energy. The results hold for both 30 and 50 years life time even though the clay material is less durable and has to be replaced. So, it is recommended that high thermal resistance material is more preferable for tropical weather.

5.2 Case Study 2: Assessing impact of material transition and thermal comfort models on embodied and operational energy in vernacular dwellings (India) This research was conducted by KI Praseeda, Monto Mani and BV Venkatrama Reddy to study the increase in EE of the dwelling attributed to change in wall materials and assesses operational energy in traditional dwelling with regard to change in wall material and climatic location. The paper adopts two popular thermal-comfort models, viz., ASHRAE comfort standards and TSI by Sharma and Ali to investigate thermal comfort aspects and impact of these comfort models on OE assessment in traditional dwellings.

The objective of this study was to study the impact of transition in material use and adoption of different thermal comfort models on energy use in vernacular dwellings. A naturally ventilated vernacular dwelling in Sugganahalli, a village close to Bangalore (India), set in warm – humid climate is considered for present investigations on impact of transition in building materials, change in climatic location and choice of thermal comfort models on energy in buildings

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Case Study For, the purpose of assessment, a dwelling that had adopted locally available materials had to be considered. Therefore, from a preliminary survey, one typical courtyard house was identified based on the commonality in the floor plan, design features and living habits.

The dwelling had the following features: 

  

It comprised of four bedrooms, three kitchens, a common open bathroom and a central open courtyard (50 m2) with Mangalore (clay) tiled corridor (100 m2) on three sides for rearing livestock.

It had a built up area of 400m2.

The main entrance faces north and opens out onto the road.

Two families currently occupy the house –three females, two males and a boy.

Figure 5.1: Floor plan of the dwelling. Source: Praseeda, Mani and Venkatrama, 2013.

The Traditional materials and construction details used are as follows: Walls:

Rubble masonry with mud mortar – 450mm thick, mud plastering on interior walls

Roof type Mud roof:

Wooden plank stone slab compacted mud – 300mm thick

Pitched roof:

Standard Mangalore tiles on wooden rafters

Flooring:

Rammed earthen flooring with a screed of cow dung/cement

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Calculation of embodied energies Table 5.7 shows the embodied energy calculation for the dwelling with different wall materials and existing roofing configurations(Source: Praseeda, Mani and Venkatrama, 2013): Table 5.7: Embodied energy calculation for the dwelling. (Source: Praseeda, Mani and Venkatrama, 2013).

Type of wall

EE of the dwelling

GJ/m2

MJ

Rubble stone masonry

66347.51

0.17

66347.51

0.17

Burnt clay brick masonry

658753.8

1.65

Cement stabilized soil block masonry

190313

0.48

Naturally (Adobe)

compacted

soil

block

The result shows that replacing rubble stone masonry with burnt clay brick masonry and stabilized soil block masonry would increase the EE of the dwelling by 9.7 times (870%) and 2.8 times (182%) respectively. This shows that the transition of material used in walls from stone to burnt clay bricks has significant impact on EE of the dwelling. Projecting this impact for the entire group of vernacular dwellings in the country, this transition would cause huge implication on energy demand of the country.

Calculation of operational energy For the research, operational energy of three different wall materials; rubble stone masonry, burnt clay brick masonry and stabilized soil blocks, for three different thermal comfort models in two different climate zones was assessed using building simulation model. OE for the dwelling included energy for thermal comfort and lighting. Total operational energy (sum of thermal comfort energy and lighting energy) of the dwelling for different scenarios was then expressed in terms of GJ/m2/year. Table 1 summarizes the seasonal OE estimates for the traditional dwelling based on the ASHRAE model, for various wall configurations and climatic zones. Energy for indoor lighting was estimated at 1706.31 kWh/year for all the cases.

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Table 5.8: Operational energy for dwellings in different climatic zones Source: (Praseeda, Mani and Venkatrama, 2013)

Figure 5.2: Comparison of annual air-conditioning energy for the traditional dwelling with varying wall configurations and climatic zones, with ASHRAE 55 as the reference model (Source: Praseeda, Mani and Venkatrama, 2013)

Conclusion From the results, it is clear that there is negligible variation in OE(less than 1kWh/m2 per year) for warm-humid and moderate climate zone. Similarly, for identical wall configurations also, there is negligible variation in the OE for the two wall systems. However, in case of hot and dry zone, there is significant variation of OE( nearly 4kWh/m2 per year) for the different wall systems as well as identical wall systems when compared to the other two climatic zones.

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5.3 Case Study 3: Embodied Energy and CO2 coefficients for NZ Building Materials by Andrew Alcorn Andrew Alcorn conducted a study in 2003 to assess the embodied energy and CO2 emissions of building materials. The research grew out of demand for detailed knowledge of emerging environmental impacts to progress towards sustainable practices.

According to Alcorn, the principal source of CO2 in building materials is the combustion of fossil fuel in their production, or the use of ingredients or energy sources that in turn required a significant use of fossil fuel. By the application of the known CO2 emissions of different fuels to those used in producing individual building materials, an overall embodied CO2 content can be established for each material. For this purpose, a process-based hybrid energy analysis was used as the basis of this research.

Methodology In this study, the data from a previous study (Alcorn, 1998) was used and upgraded to include embodied CO2 coefficients. Energy inputs required in each process have been analysed for their CO 2 content. What is significant and important about this study is that each material has been recalculated, with any new readily available data included, and errors or omissions rectified. An example of the changes that have occurred is recycled aluminium, where the energy of collecting scrap aluminium has been added, along with the energy of the capital equipment. No specific data was available for these particular items, but it was decided to include proxies from closely related operations to improve the consistency of the results.

For the research, a process-based hybrid energy analysis was used. This means that individual production processes are first analysed as far as is practical. All ingredients and energy sources used are analysed, with factors included for the production and distribution of energy, the transport of ingredients and the energy of the capital equipment used to make the material. The total energy is then divided by the output of the production facility.

However, there are also a few shortcomings in the research. Solar Energy, which is required for the growing of trees is not included, energy of human labour is not included. The calorific value of an ingredient used as a physical feedstock to a process is not included. The energy of waste or recycled products is treated as zero for physical ingredients. The energy of local transport to the material production site is included, but not the energy of transport from the factory gate to the point of use.

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As an example, recycled steel was used for analysis. This study treats the whole process of producing the material as one operation. It organizes the analysis into ingredients, energy inputs, transport, capital equipment, outputs, and extra information. This differs from other methods which breakdown the analysis into production stages. Majority of the embodied energy coefficients were taken from Alcorn, 1998. The embodied energy coefficient for an ingredient is converted to a coefficient per kilogram of product by relating it to the output of the operation studied. Emission factors are applied to arrive at an emission per kilogram of product for each ingredient. Where some or all of this is from imported energy or imported ingredients it is noted separately. A subtotal of the energy and CO 2 coefficients is used to calculate the capital equipment energy. This is the energy to build and maintain the plant used for the manufacturing operation.

All the energy inputs including the electricity for the steel plant, embodied energy of product, CO 2 emissions due to electricity and gas, transport energy, capital equipment and outputs were calculated.

Subtotals for the embodied energy coefficient and CO2 emissions coefficient are used to calculate the capital equipment energy. Totals are the sum of the subtotal and capital equipment energy.

Conclusion This research provides a basis for detailed analysis of buildings and building elements beyond the simple, and inaccurate method of converting national energy figures into CO2 figures, or making inevitable but misleading assumptions about fuel types for particular materials. The embodied CO2 coefficients show a different pattern from the embodied energy coefficients, with less of a gap between the highest group and the next highest, and at the other end of the scale some materials having negative values. Materials like Aluminium, Copper HDPE, extruded PVC, stainless steel, copper wire and rod, and copper sheet have the highest amount of embodied energy and CO2 emissions. However, all timber products, that have negative values, representing a net absorption of CO2.

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CHAPTER 6: PRIMARY CASE STUDY AND ANALYSIS 6.1 Methodology The building envelope contributes significantly to the overall embodied energy of the building and hence is an important parameter to consider. Moreover, the envelope also leads to changes in embodied as well as operational energies with changing configurations and orientations of the built form. Therefore, the effect of built form, orientation and materials in the envelope are considered.

Based on previous secondary case studies a typical guest room block of a business hotel-Hyatt Amritsar was considered for simulation. The original plan obtained was an L shaped plan. The original plan was modified in terms of built form to get four different options keeping the room sizes and floor area constant. These four different options are:

Figure 6.2: The original L shaped Plan.

Source: Project Manager Figure 6.1: Courtyard shape plan shaped plan with singly loaded corridor. Source: Author

Figure 6.4: : Singly loaded corridor plan. Source: Author Figure 6.3: Doubly loaded corridor plan. Source: Author

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Operational energy was then found out for each option in 8 different orientations and the case with the least operational energy was noted. In the simulation of operational energy, the following specifications were adopted as default specifications for all four cases: Wall material

-

Burnt clay bricks with 15mm thick 1:6 cement sand plaster

External wall finish

-

Enamel Paint

Windows

-

Fixed glass in timber frame

Roof Slab

-

1:2:4 RCC slab with steel rebars

Roof waterproofing

-

Bitumen membrane at 3mm thick

Roof insulation

-

50mm thick Brick bat coba

Roof finish

-

Clay tiles laid in 20mm thick cement plaster

For the case with the least OE, four different types of envelope systems including the default one were applied for analysis and calculation of embodied energy and hence cumulative energy which are:    

Burnt clay bricks with paint Curtain wall with aluminium framing Stone cladding Cavity Wall

In the process of simulation of the above envelope systems:  

The areas, built form, interior specifications are kept constant for the case with the least OE. The structure is assumed to be made of 1:2:4 RCC.

Now, to understand the effect of built form and materials on energy consumption, the analysis is done in two phases:

Embodied Energy or the pre use phase analysis The embodied energy 4 different envelopes of the building are modelled in Autodesk Revit 2014 to find out the exact quantities of the materials used in the construction of the envelope. The specifications used were same as those being used in Delhi these days. After listing down the exact quantity of every material in the envelope, the quantities were multiplied with the energy coefficients

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to obtain the embodied energy share of different materials and then summed up to find the total embodied energy of the envelope. The results for the different options are then compared.

Operational Energy or the use phase analysis To calculate the operational energy, the four different options were modelled in eQUEST software and also the simulation for each envelope system was done for different orientations to know the operational energy changes that occur for different orientations for the four options. The results are obtained and compared.

The total energy of the built form, i.e. embodied energy + operational energy is calculated for the different options and compared.

Summary of Methodology

Operational •Calculation of Operational energy for different built forms in 8 different orientations

Energy

•Noting down the case with least operational energy Least OE

Embodied

•Application of four different envelope systems on the above case and calculation of embodied energy for each case

energy

Cumulative

•Calculation of cumulative enegy for each case over a period of 50 years by adding the recurring embodied energy and operational energy for 50 years

Energy

Effect of Insulation

•To study the effect of insulation of the envelope system with the least cumulative energy

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6.2 Analysis of Operational Energy To find out the best possible option, first the operational energy has been calculated for the four different built forms in 8 different orientations. The most efficient built form has been further analysed in terms of changes in envelope material and insulation.

6.2.1 Case 1: The original L shaped Plan

Figure 6.5: The original L shaped Plan. Source: Project Manager

Figure 6.5 shows the original L shaped plan of the hotel as obtained from the architect.    

Only the typical guest room floor has been considered for simulation as these accounts for majority of the part of the hotel.

The floor coverage of the guest room floor is 770m2.

For simulation, four different envelope options have been considered for the same plan. The options have been chosen on the basis of the most prevalent construction practices in India.

In the envelope, the following elements are considered for simulation:       



Wall material External plaster Wall finish Windows Roof Waterproofing Roof insulation Roof finish

All the interior elements and finishes have not been considered since the focus of the research is only on the building‟s envelope.

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Calculation of Operational energy

Table 6.1: Operational energy values for L shaped plan. Source: Author.

Orientation

North

NorthWest

West

South

South

South East

East

North East

8515080

8349480

8134200

8492400

West Operational Energy(MJ)

8382240

8390880

8079480

8615880

Operational Energy 8700000

8600000 8500000 8400000 8300000 8200000

Operational Energy

8100000 8000000 7900000 7800000 North

North West

West

South South West

South East

East

North East

Figure 6.6: Variation of operational with orientation for L shaped plan. Source: Author

Therefore, the graph states that the highest operational energy occurs in the south west direction and the lowest occurs in the west direction. Therefore, for comparison, we take the least value.

The least value of operational energy = 8079480 MJ

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6.2.2 Case 2: The Courtyard Plan

Figure 6.7: The courtyard plan. Source: Author

Figure 6.7 shows the O shape or the courtyard plan that was created by the author by altering the original L shape plan. In doing so, the following was considered:     

Only the typical guest room floor has been considered for simulation as these accounts for majority of the part of the hotel.

The floor coverage of each floor has been kept the same i.e., 760m2.

The sizes of rooms and services areas have been kept the same.

For simulation, four different envelope options have been considered for the same plan. The options have been chosen on the basis of the most prevalent construction practices in India.

In the envelope, the following elements are considered for simulation:       



Wall material External plaster Wall finish Windows Roof Waterproofing Roof insulation Roof finish

All the interior elements and finishes have not been considered since the focus of the research is only on the building‟s envelope.

Calculation of Operational Energy

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Table 6.2: Operational energy values for courtyard shaped plan. Source: Author.

Orientation

North

NorthWest

West

South

South

South East

East

North East

8478000

9039600

8878320

8851572

West Operational Energy(MJ)

8560800

8942400

8748000

8866800

Operational Energy Courtyard 9100000 9000000 8900000 8800000 8700000 8600000 Operational Energy Courtyard

8500000 8400000 8300000 8200000

8100000 North North West South South South East North West West East East Figure 6.8: Variation of operational with orientation for courtyard shaped plan. Source: Author

Therefore, the graph states that the highest operational energy occurs in the south east direction and the lowest occurs in the south direction. Therefore, for comparison, we take the least value.

The least value of operational energy = 8478000 MJ

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6.2.3 Case 3: Singly loaded Corridor Plan

Figure 6.9: The Singly loaded corridor plan. Source: Author

Figure 6.9 shows the singly loaded corridor plan that was created by the author by altering the original L shape plan. In doing so, the following was considered:     

Only the typical guest room floor has been considered for simulation as these accounts for majority of the part of the hotel.

The floor coverage of each floor has been kept the same i.e., 760m2.

The sizes of rooms and services areas have been kept the same.

For simulation, four different envelope options have been considered for the same plan. The options have been chosen on the basis of the most prevalent construction practices in India.

In the envelope, the following elements are considered for simulation:       



Wall material External plaster Wall finish Windows Roof Waterproofing Roof insulation Roof finish

All the interior elements and finishes have not been considered since the focus of the research is only on the building‟s envelope.

Table 6.3: Operational energy values for singly loaded corridor plan. Source: Author.

Orientation

North

NorthWest

West

South

South

South East

East

North East

8079840

9070920

10348200

9605160

West Operational Energy(MJ)

8083440

9182880

10074600

9136800

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Operational Energy Singly Loaded 12000000

Energy(MJ)

10000000 8000000 6000000

Operational Energy Singly Loaded

4000000 2000000 0 North North West South South South West West East

East

North East

Figure 6.10: Variation of operational with orientation for singly loaded corridor plan. Source: Author

Therefore, the graph states that the highest operational energy occurs in the east direction and the lowest occurs in the south direction. Therefore, for comparison, we take the least value.

The least value of operational energy = 8079840 MJ

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6.2.4 Case 3: Doubly loaded Corridor Plan

Figure 6.11: The Doubly loaded corridor plan. Source: Author

Figure 6.11 shows the doubly loaded corridor plan that was created by the author by altering the original L shape plan. In doing so, the following was considered:     

Only the typical guest room floor has been considered for simulation as these accounts for majority of the part of the hotel.

The floor coverage of each floor has been kept the same i.e., 760m2.

The sizes of rooms and services areas have been kept the same.

For simulation, four different envelope options have been considered for the same plan. The options have been chosen on the basis of the most prevalent construction practices in India.

In the envelope, the following elements are considered for simulation:       



Wall material External plaster Wall finish Windows Roof Waterproofing Roof insulation Roof finish

All the interior elements and finishes have not been considered since the focus of the research is only on the building‟s envelope.

Calculation of operational energy Table 6.4: Operational energy values for doubly loaded corridor plan. Source: Author.

Orientation

North

NorthWest

West

South

South

South East

East

North East

7554960

8223480

8693280

8175960

West Operational Energy(MJ)

7554960

8223480

8693280

8175960

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11000000 10500000

Energy(MJ)

10000000 9500000

Operational Energy L shape

9000000

Operational Energy Singly Loaded

8500000

Operational Energy Doubly Loaded

8000000

Operational Energy Courtyard

7500000 7000000 North

North West

West

South South West

South East

East

North East

Figure 6.12: Variation of operational with orientation for doubly loaded corridor plan. Source: Author

Therefore, the graph states that the highest operational energy occurs in the west direction and the lowest occurs in the south direction. Therefore, for comparison, we take the least value.

The least value of operational energy = 7554960 MJ After simulating all the four options of built form, it is found that the least operational energy occurs in the case of doubly loaded corridor plan in the south direction. Therefore, we consider this option for further calculation of embodied energy and cumulative energy.

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6.3 Analysis on changes in envelope material On simulating the OE of all the four built forms, it was found out that the most efficient one was the doubly loaded corridor plan. So, this case has been considered to study the effect of changes in envelope material and insulation. To study this effect, four different options of envelope have been applied on the doubly loaded corridor plan.

Figure 6.13: The Doubly loaded corridor plan. Source: Author

6.3.1 Option A: Burnt Clay bricks with paint The general specifications of the envelope are as follows:

Wall material

-

Burnt clay bricks with 15mm thick 1:6 cement sand plaster

External wall finish

-

Enamel Paint

Windows

-

Fixed glass in timber frame

Roof Slab

-

1:2:4 RCC slab with steel rebars

Roof waterproofing

-

Bitumen membrane at 3mm thick

Roof insulation

-

50mm thick Brick bat coba

Roof finish

-

Clay tiles laid in 20mm thick cement plaster

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The calculations for the embodied energy of the building envelope for the above plan are as follows:

Building Envelope Component

Quantity

Embodied

Embodied

Energy/unit(MJ)

Energy(MJ)

Brick masonry(m3)

546.4

4482

2448964.8

External Plaster(m3)

36.2

3200

115840

External wall finish(m2)

2376.5

6.5

15447.25

Windows - glass(m3)

18.2

37550

683410

Windows – timber frame(m3)

30.2

1550

46810

Exterior Columns-concrete(m3)

200.4

3180

637272

43

1352900.4

Exterior

Columns

- 31462.8

reinforcement(kg) Roof slab concrete(m3)

107.43

3180

341627.4

Roof slab Reinforcement(kg)

8433.25

43

362629.75

Roof waterproofing(m3)

2.15

45420

97653

Roof insulation(m2)

716.19

148.25

106175.1675

Roof mortar(m3)

14.32

3200

45824

Roof finish

716.19

112

80213.28

Total embodied energy

6334767.05

Therefore, the total embodied energy due to the building‟s envelope is 6334767.05 or 6334.76 GJ. All the values of embodied energy coefficients have been taken from „Practical handbook on energy conservation in buildings by Indian buildings congress‟.

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Embodied Energy share of Building Envelope Componet

16%

Wall 41%

Windows Exterior Columns

31%

Roof

12%

Figure 6.14: Embodied Energy share of Building Envelope Componet for option A. Source: Author

Embodied Energy share of Building Envelope Material 2% 1%

Brick Plaster Paint

27%

40%

Glass Timber Concrete

15%

Steel

11% 1%

0%

Bitumen

3%

Clay tiles

Figure 6.15: Embodied Energy share of Building Envelope Material for option A. Source: Author

From the above charts, it is clear that • Walls are the major contributors of embodied energy due to the high embodied energy of bricks. • However, exterior columns also contribute to a significant amount due to the high contribution of embodied energy of steel and concrete.

Calculation of Recurrent Embodied Energy for Option A Generally, most of the materials or building components deteriorate over a period of time and have to be replaced or reapplied. This leads to an increase in embodied energy over a period of time. On the

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basis of information gathered from the engineer and online sources, the following pattern of change of components in the envelope was obtained: Building Envelope Component

Replacement Period

External wall paint

5 years

Windows

7 years

Roof Waterproofing

15 years

Insulation

10 years

Roof finish

10 years

Therefore, on the basis of calculations, the following values of embodied energies over a period of 50 years were obtained: Time(years)

Embodied Energy(MJ)

0

6334767.05

5

6350214.3

10

7328094

15

7441194.25

20

8419073.94

25

8434521.19

30

9510053.88

35

9525501.13

40

10503380.82

45

10616481.07

50

11594360.76

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Therefore, the embodied energy at the end of 50 years = 11594360.76 MJ= 11594.36 GJ

Now, let us analyse the operational energy of the plan with the above envelope system. Since, the operational energy of any building changes with orientation, analysis was done on 8 different orientations of the same envelope system. The results are as follows:

Table 6.5: Operational energy values for option A. Source: Author.

Orientation

North

NorthWest

West

South

South

South East

East

North East

7554960

8223480

8693280

8175960

West Operational Energy(MJ)

7554960

8223480

8693280

8175960

Operational Energy 10000000 9000000 8000000 Energy(MJ)

7000000 6000000 5000000

Operational Energy Doubly Loaded

4000000 3000000 2000000 1000000 0 North

North West

West

South South West

South East

East

North East

Figure 6.16: Variation of operational energy with orientation for option A. Source: Author.

Therefore, the graph states that the highest operational energy occurs in the west direction and the lowest occurs in the north and south direction. Therefore, for calculation, we take the least value.

The least value of operational energy = 7554960 MJ Operational Energy at the end of 50 years = 7554960 X 50 = 377748000 MJ = 377748 GJ Cumulative Energy = Embodied energy at the end of 50 years + Operational Energy at the end of 50 years = 11594.36 + 377748= 389342.36 GJ

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450000000 400000000 350000000 300000000 Recurring Embodied Energy

250000000

Initial Embodied Energy

200000000

Operational Energy

150000000

Cumulative Energy

100000000 50000000 0 0

5

10

15

20

25

30

35

40

45

50

Figure 6.17: Energy v/s years - option A. Source: Author

The graph shows that with time the initial embodied energy remains the same, however, the recurring embodied energy gradually increases. The embodied energy however, is initially zero but takes over the envelopes embodied energy after a period of 1.5-2 years.

6.3.2 Option B: Curtain Wall System The general specifications of the envelope are as follows:

Wall material

-

Glass curtain wall with aluminium framing and silicone sealant

Roof Slab

-

1:2:4 RCC slab with steel rebars

Roof waterproofing

-

Bitumen membrane at 3mm thick

Roof insulation

-

50mm thick Brick bat coba

Roof finish

-

Clay tiles laid in 20mm thick cement plaster

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The calculations for the embodied energy of the building envelope for the option are as follows:

Building Envelope Component

Quantity

Embodied

Embodied

Energy/unit(MJ)

Energy(MJ)

Curtain wall - glass(m3)

89.4

37550

3356970

Curtain wall mullions(kg)

15940.31

191

3044599.21

Curtain wall sealant(kg)

398.46

157

62558.22

Exterior Columns-concrete(m3)

200.4

3180

637272

Exterior Columns -reinforcement(kg)

31462.8

43

1352900.4

Roof slab concrete(m3)

107.43

3180

341627.4

Roof slab Reinforcement(kg)

8433.25

43

362629.75

Roof waterproofing(m3)

2.15

45420

97653

Roof insulation(m2)

716.19

148.25

106175.168

Roof mortar(m3)

14.32

3200

45824

Roof finish(m2)

716.19

112

80213.28

Total embodied energy

9488422.43

Therefore, the total embodied energy due to the envelope is 9488422.43 MJ or 9488.42 GJ which is much more than that of the previous case.

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Embodied Energy share of Building Envelope Componet

11% Curtain wall 21%

Exterior Columns Roof

68%

Figure 6.18: Embodied Energy share of Building Envelope Component for option B. Source: Author.

Embodied Energy share of Building Envelope Material 1%

1% Glass Aluminium

18% 36%

Silicone Concrete

10%

Steel 1% 33%

Bitumen Clay tiles

Figure 6.19: Embodied Energy share of Building Envelope Material for option B. Source: Author

From the above charts, it is clear that • Curtain wall is the major contributor of embodied energy due to the high embodied energies of glass and aluminium • However, exterior columns also contribute to a significant amount due to the high contribution of embodied energy of steel and concrete.

Calculation of Recurrent Embodied Energy for Option B On the basis of information gathered from the engineer and online sources, the following pattern of change of components in the envelope was obtained:

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Building Envelope Component

Replacement Period

Curtain wall glass

Once in 50 years

Curtain wall frame

Once in 50 years

Curtain wall sealant

15 years

Roof Waterproofing

15 years

Insulation

10 years

Roof finish

10 years

For information obtained regarding the curtain wall, it was found that it is changed entirely once in a 50 year period but not all panels and frames are changed at the same time. So in order to find a value of increase in embodied energy for a period of 5 years, and average value was taken by dividing total increase in embodied energy of the curtain wall by 50 years. Therefore, on the basis of calculations, the following values of embodied energies over a period of 50 years were obtained: Time(years)

Embodied Energy(MJ)

0

9488422.43

5

10128579.43

10

11000948.87

15

11801317.09

20

12673686.53

25

13313843.53

30

14346424.19

35

14986581.19

40

15858950.63

45

16659318.85

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50

17531688.29

Therefore, the embodied energy at the end of 50 years = 17531688.29MJ = 17531.68 GJ Now, let us analyse the operational energy of the plan with the above envelope system. Since, the operational energy of any building changes with orientation, analysis was done on 8 different orientations of the same envelope system. The results are as follows:

Table 6.6: Operational energy values for option B. Source: Author.

North

Orientation

NorthWest

West

South

South

South East

East

North East

10278000

11299320

12434760

11292120

West 10278000

Operational Energy(MJ)

11298960

12434400

11292120

Operational Energy for Curtain wall system 14000000 12000000

Enegy(MJ)

10000000 8000000 Operational Energy Doubly Loaded

6000000 4000000 2000000 0 North North West South South South West West East

East

North East

Figure 6.20: Variation of operational energy with orientation for option B. Source: Author.

The above graph states that the highest operational energy occurs in the west direction and the lowest occurs in the south and north directions. Therefore, for comparison, we take the least value.

The least value of operational energy = 10278000 MJ Operational Energy at the end of 50 years = 10278000 X 50 = 513900000MJ = 513900 GJ Cumulative energy = Embodied energy at the end of 50 years + Operational Energy at the end of 50 years = 17531.68 GJ + 513900 GJ = 531431.68 GJ

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600000000

500000000

400000000 Recurring Embodied Energy Initial Embodied Energy

300000000

Operational Energy Cumulative Energy

200000000

100000000

0 0

5

10

15

20

25

30

35

40

45

50

Figure 6.21: Energy v/s years - option B. Source: Author.

The graph shows that with time the initial embodied energy remains the same, however, the recurring embodied energy gradually increases. The embodied energy however, is initially zero but takes over the envelopes embodied energy after a period of 1.5-2 years.

6.3.3 Option C: Stone Cladding The general specifications of the envelope are as follows: Wall material

-

External wall finish

Burnt clay bricks -

30mm thick stone cladding laid on 20mm thick 1:6 cement plaster

Windows

-

Fixed glass in timber frame

Roof Slab

-

1:2:4 RCC slab with steel rebars

Roof waterproofing

-

Bitumen membrane at 3mm thick

Roof insulation

-

50mm thick Brick bat coba

Roof finish

-

Clay tiles laid in 20mm thick cement plaster

The calculations for the embodied energy of the building envelope for the above plan are as follows:

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Building Envelope Component

Quantity

Embodied

Embodied

Energy/unit(MJ)

Energy(MJ)

Brick masonry(m3)

546.4

4482

2448964.8

External Plaster(m3)

46.8

3200

149760

External wall finish - stone(m3)

71.9

1890

135891

Windows - glass(m3)

18.2

37550

683410

Windows – timber frame(m3)

30.2

1550

46810

Exterior Columns-concrete(m3)

200.4

3180

637272

Exterior Columns -

31462.8

43

1352900.4

Roof slab concrete(m3)

107.43

3180

341627.4

Roof slab Reinforcement(kg)

8433.25

43

362629.75

Roof waterproofing(m3)

2.15

45420

97653

Roof insulation(m2)

716.19

148.25

106175.1675

Roof mortar(m3)

14.32

3200

45824

Roof finish(m2)

716.19

112

80213.28

reinforcement(kg)

Total embodied energy

6489130.798

Therefore, the total embodied energy due to the envelope is 6489130.8 MJ.

962432.44

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Embodied Energy share of Building Envelope Componet

16%

Wall 42%

Windows Exterior Columns

31%

Roof 11%

Figure 6.22: Embodied Energy share of Building Envelope Component for option C. Source: Author.

Embodied Energy share of Building Envelope Material 2% 1%

Brick

Plaster 26%

39%

Stone Glass Timber

15%

Concrete

11% 1%

2%

3%

Steel

Figure 6.23: Embodied Energy share of Building Envelope Material for option C. Source: Author

From the above charts, it is clear that 

In terms of material, brick is the major contributor to the overall embodied energy.



In terms of component, exterior columns are the major contributors due to the high embodied energies of steel and concrete.



Stone has a slightly higher embodied energy than external wall paint.

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Calculation of Recurrent Embodied Energy for Option C On the basis of information gathered from the engineer and online sources, the following pattern of change of components in the envelope was obtained: Building Envelope Component

Replacement Period

Stone cladding

100+ years

Windows

7 years

Roof Waterproofing

15 years

Insulation

10 years

Roof finish

10 years

Therefore, on the basis of calculations, the following values of embodied energies over a period of 50 years were obtained: Time(years)

Embodied Energy(MJ)

0

6489130.798

5

6489130.798

10

7451563.238

15

7549216.238

20

8511648.678

25

8511648.678

30

9571734.118

35

9571734.118

40

10534166.558

45

10631819.558

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50

11594251.998

Therefore, the embodied energy at the end of 50 years = 11594252 MJ = 11594.25 GJ

Now, let us analyse the operational energy of the plan with the above envelope system. Since, the operational energy of any building changes with orientation, analysis was done on 8 different orientations of the same envelope system. The results are as follows:

Table 6.7: Operational energy values for option C. Source: Author.

Orientation

North

NorthWest

West

South West

South

South East

East

North East

Operational Energy (MJ)

7415280

8151840

8548920

8118000

7415280

8151840

8548920

8118000

Operational Energy for Option C: Stone Cladding 9000000 8000000

Energy (MJ)

7000000 6000000 5000000 Operational Energy

4000000 3000000 2000000 1000000

0 North

North West

West

South West

South

South East

East

North East

Figure 6.24: Variation of operational energy with orientation for option C. Source: Author.

The above graph states that the highest operational energy occurs in the east and west direction and the lowest occurs in the south and north directions. Therefore, for comparison, we take the least value.

The least value of operational energy = 7415280 MJ Operational Energy at the end of 50 years = 7415280 X 50 = 370764000MJ = 370764 GJ Cumulative Energy after 50 years = Embodied energy at the end of 50 years + Operational Energy at the end of 50 years = 11594.25 GJ + 370764 GJ = 382358.25 GJ

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450000000 400000000 350000000

300000000 Recurring Embodied Energy

250000000

Initial Embodied Energy

200000000

Operational Energy

150000000

Cumulative energy

100000000 50000000 0 0

5

10

15

20

25

30

35

40

45

50

Figure 6.25: Energy v/s years - option C. Source: Author.

The graph shows that with time the initial embodied energy remains the same, however, the recurring embodied energy gradually increases. The embodied energy however, is initially zero but takes over the envelopes embodied energy after a period of 1.5-2 years.

6.3.4 Option D: Cavity Wall The general specifications of the envelope are as follows: Wall material

-

Burnt clay bricks with 15mm thick 1:6 cement sand plaster. Outer wall-230mm thick and inner wall 115mm thick

Cavity

-

External wall finish

Air Gap -

Enamel Paint

Windows

-

Fixed glass in timber frame

Roof Slab

-

1:2:4 RCC slab with steel rebars

Roof waterproofing

-

Bitumen membrane at 3mm thick

Roof insulation

-

50mm thick Brick bat coba

Roof finish

-

Clay tiles laid in 20mm thick cement plaster

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The calculations for the embodied energy of the building envelope for the above plan are as follows: Building Envelope Component

Quantity

Embodied

Embodied

Energy/unit(MJ)

Energy(MJ)

Brick masonry(m3)

815.6

4482

3655519.2

External Plaster(m3)

36.2

3200

115840

External wall finish(m3)

2376.5

6.5

15447.25

Windows - glass(m3)

18.2

37550

683410

Windows – timber frame(m3)

30.2

1550

46810

Exterior Columns-concrete(m3)

200.4

3180

637272

Exterior Columns -

31462.8

43

1352900.4

Roof slab concrete(m3)

107.43

3180

341627.4

Roof slab Reinforcement(kg)

8433.25

43

362629.75

Roof waterproofing(m3)

2.15

45420

97653

Roof insulation(m2)

716.19

148.25

106175.1675

Roof mortar(m3)

14.32

3200

45824

Roof finish(m2)

716.19

112

80213.28

reinforcement(kg)

Total embodied energy

7541321.448

Therefore, the total embodied energy due to the envelope is 7541321.45 MJ.

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Embodied Energy share of Building Envelope Componet

14% Wall Windows 26%

50%

Exterior Columns Roof

10%

Figure 6.26: Embodied Energy share of Building Envelope Componet for option D. Source: Author.

Embodied Energy share of Building Envelope Material 1% 1%

Brick Plaster Paint

23%

Glass

50% 13%

Timber Concrete Steel

1%

9% 0%

Bitumen

2%

Clay tiles

Figure 6.27: Embodied Energy share of Building Envelope Material for option D. Source: Author.

From the above charts, it is clear that 

In this case, maximum contribution is due to the walls as double layer of brick masonry is used



Exterior columns also contribute to a significant amount due to the high contribution of embodied energy of steel and concrete.

Calculation of Recurrent Embodied Energy for Option D On the basis of information gathered from the engineer and online sources, the following pattern of change of components in the envelope was obtained:

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Building Envelope Component

Replacement Period

External wall paint

5 years

Windows

7 years

Roof Waterproofing

15 years

Insulation

10 years

Roof finish

10 years

Therefore, on the basis of calculations, the following values of embodied energies over a period of 50 years were obtained: Time(years)

Embodied Energy(MJ)

0

7541321.45

5

7556768.7

10

8534648.39

15

8647748.64

20

9625628.33

25

9641075.58

30

10732055.52

35

10747502.77

40

11725382.46

45

11838482.71

50

12816362.4

Therefore, the embodied energy at the end of 50 years = 12816362.4 MJ= 12816.36 GJ

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Now, let us analyse the operational energy of the plan with the above envelope system. Since, the operational energy of any building changes with orientation, analysis was done on 8 different orientations of the same envelope system. The results are as follows:

Table 6.8: Operational energy values for option D. Source: Author.

Orientation

North

NorthWest

West

South

South

South East

East

North East

7170480

7918200

8284680

8284680

West Operational Energy(MJ)

7170480

7918200

8284680

7857000

Operational Energy 9000000 8000000 7000000 Energy(MJ)

6000000 5000000 4000000

Operational Energy

3000000

2000000 1000000 0 North North West

West

South South West

South East

East

North East

Figure 6.28: Variation of operational energy with orientation for option D. Source: Author.

Therefore, the graph states that the highest operational energy occurs in the east and west direction and the lowest occurs in the north and south direction. Therefore, for comparison, we take the least value.

The least value of operational energy = 7170480 MJ Operational Energy at the end of 50 years = 7170480 X 50 = 358524000 MJ = 358524 GJ Cumulative Energy after 50 years = Embodied energy at the end of 50 years + Operational Energy at the end of 50 years = 12816.36 GJ + 358524 GJ = 371340.36 GJ

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400000000 350000000 300000000 250000000

Recurring Embodied Energy Initial Embodied Energy

200000000

Operational Energy 150000000

Cumulative energy

100000000 50000000 0 0

5

10

15

20

25

30

35

40

45

50

Figure 6.29: Energy v/s years – option D. Source: Author.

The graph shows that with time the initial embodied energy remains the same, however, the recurring embodied energy gradually increases. The embodied energy however, is initially zero but takes over the envelopes embodied energy after a period of 1.5-2 years.

Findings: On finding the embodied, operational and cumulative energies for the four different options of envelope, we do a comparative analysis to find out the most energy efficient option to carry out further analysis.

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600000

500000

Energy(GJ)

400000 Embodied Energy 300000

Operational Energy Cumulative Energy

200000

100000

0 Brick masonry

Curtain wall Stone Cladding

Cavity Wall

Figure 6.30: Variation of energy with envelope options. Source: Author

From the above graph, it is clear that the most energy intensive option is the curtain wall system, whereas the most energy efficient is the cavity wall system. Till now, we have found out that the most energy efficient combination is that of the doubly loaded corridor plan with cavity wall as the envelope material in the north-south orientation. However, to further reduce the overall energy of the building, we study the effect of insulation for this combination.

6.4 Effect of Insulation In order to reduce the overall energy for the option of cavity wall in doubly loaded corridor plan, we add polystyrene insulation to the roof and walls of various thicknesses and find out the corresponding values of operational energy for each and their effect in the north-south orientation as shown in the table below: Table 6.9: Operational energy values for varying insulations. Source: Author.

Insulation thickness

1 inch

2 inch

3 inch

4 inch

Enery value when 7003080 applied to roof(MJ)

6989400

6982560

6977520

Enery value when 5991120 applied to walls(MJ)

5947560

5928840

5915160

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

7500000

7000000

6500000 Roof Wall

6000000

5500000

5000000 Uninsulated

1 inch

2 inch

3 inch

4 inch

Figure 6.31: Variation of operational energy with insulation. Source: Author.

Therefore, from the above values, we notice that though there is little reduction in the operational energy when the roof is insulated, there is significant saving when the walls are insulated. From the above graph, we also infer that on initially adding insulation to the envelope, there is a drastic reduction in the operational energy; however, as we keep on increasing the insulation values, the effect of insulation keeps on reducing.

Net savings in energy in case of roof insulation is upto 3% whereas in case of wall insulation, the saving is upto 18%.

According to the graph, we see that, the least amount of operational energy with insulation occurs in the north orientation. Therefore, now we analyse the net energy saving due to insulation: Total energy with wall insulation at the end of 50 years = 5915160 X 50 = 295758000 MJ= 295758 GJ

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Energy(MJ)

400000000 350000000

Recurring Embodied Energy

300000000

Initial Embodied Energy

250000000 200000000

Operational Energy without insulation

150000000

Operational Energy with insulation

100000000

Cumulative energy

50000000

Cumulative energy with insulation

0

0

5

10

15

20

25

30

35

40

45

50

Figure 6.32: Energy v/s Years with and without insulation. Source: Author.

Total savings in energy = cumulative energy at 50 years without insulation – cumulative energy at 50 years with insulation = 371340.36 GJ – 308574.36 GJ = 62766 GJ = 17435000 kwh.

Therefore, annual savings in energy = 17435000/50 = 348700 kwh Annual savings per meter square of building = 45 kwh/m2 Which is about 17% energy saved.

6.5 Effect of Variation in Envelope Therefore, now we analyse different methods to further reduce the operational energy in the cavity wall option of the doubly loaded corridor plan. We analyse the energy consumption by adding changes in the following aspects: 

Wall Insulation(4 inch)



Roof Insulation(3 inch)



Double glazing



Reflective glazing



Louvers



Fins



Daylight Factor

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Dissertation | Energy Efficiency through Building Envelope Performance in Hotels|

Table 6.10: Operational energy values for different variations in envelope. Source: Author.

Variation in Envelope Operational Energy(MJ)

Simple Wall Roof Double Reflective Louvers Fins Skylights Daylight Cavity Insulation Insulation glazing Glazing Factor Wall 7170480 5991120 5890680 5834880 5830560 5828040 5823360 5821200 5819040

Operational Energy 8000000 7000000

Energy(MJ)

6000000 5000000 4000000

3000000 2000000

Operational Energy

1000000 0

Figure 6.33: Variation of operational energy with variations in envelope. Source: Author.

Findings 

Initially, the operational energy changes significantly, however, with increasing variation, there is not much change and operational energy tends to remain almost constant. Hence, the effect of variation in envelope gradually decreases.



The maximum fall in OE occurs during the application ofwall insulation glass by almost 15%.



The minimum operational energy that can be achieved in case of doubly loaded corridor with cavity wall is 5819040 MJ.

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Further savings in energy = Operational energy with insulation – Operational energy with further changes in envelope = 5991120 MJ – 5819040 MJ = 172080MJ = 47800 kwh.

Annual savings per meter square of building = 6.2 kwh/m2 which is further 2.5% energy saved.

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CHAPTER 7: CONCLUSION AND RECOMMENDATIONS 7.1 Conclusion based on primary case study The primary case study was done on the basis of different parameters that affect the changes in the energy consumption of the building envelope and subsequently, the entire building. To reach to any conclusion, it is important to look at all the aspects and parameters taken into consideration together.

To understand this better, the results of the study have been categorized as follows:     

Built Form Orientation Envelope material Insulation Various changes in envelope

Built Form Form plays an important role in determining the overall climatic impact of the building. Based on the simulation results, it is noticed that the maximum amount of variation in energy occurs in the singly loaded corridor plan followed by the doubly loaded corridor plan. The L shape and courtyard plan show less variation with orientation. However, even the maximum values of energy in case of the doubly loaded corridor plan are close to those in the L shape plan. Hence, it can be rightly said that the doubly loaded corridor plan is the most suitable option in a warm climate. The L shape can also be considered relating to the site conditions.

11000000 10500000

Energy(MJ)

10000000 Operational Energy L shape Operational Energy Singly Loaded Operational Energy Doubly Loaded Operational Energy Courtyard

9500000 9000000 8500000

8000000 7500000 7000000 North North West South South South West West East

East

North East

Figure 7.1: Variation of operational energy with orientation for different built forms. Source: Author.

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It is always advisable for architects and engineers to prepare a preliminary energy model of the building to conclude which form is most suitable for a climatic region as form affects heat gain in a large way due to mutual shading and shadows cast by the building.

Orientation Different built forms show variation in operational energy differently with orientation. Hence, it is important to understand the built form before deciding upon its orientation. According to the simulation results, the singly and doubly loaded corridor plans and the courtyard plan are the most efficient in the north-south orientation whereas the L shaped plan is the most efficient in the west orientation. Hence, it is important to understand the relationship between form and orientation while designing any structure.

Guest rooms should ideally face the north and south directions in case of the double loaded corridor plan as inferred from the case study.

Envelope material The material employed in the building‟s envelope definitely is an important factor affecting the overall energy consumption of the building. The material employed not only affects the embodied energy but also the operational energy of the building as different materials have different solar heat gain factors. Based on the primary case study, the following facts were concluded: 

Curtain wall although employed by many designers as an aesthetic element in hotels these days, not only has high embodied energy but also increases the operational energy of the building due to solar heat gain. It increases the energy consumption by 110 kwh/m2 annually than the normal burnt clay bricks option.



Stone cladding although has a high initial investment cost, it has a lower recurring embodied energy as stone has a lifespan of over 100 years. Also the operational energy is also lower due to the high R-value of stone. Annual savings come out to be 5.4 kWh/ m2.



Cavity wall although has a high initial investment and higher embodied energy due to double layer of walls, it substantially reduces the operational energy and hence the cumulative energy. By employing the cavity wall, one can save up to 15 kWh/ m2 annually.

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Cumulative Energies 600000000

Energy(MJ)

500000000 400000000

Burnt Clay Bricks

300000000

Curtain Wall Stone Cladding

200000000

Cavity wall 100000000 0 0

5

10

15

20

25

30

35

40

45

50

Years Figure 7.2: Variation of Cumulative energy with time for different envelope options. Source: Author.

In terms of embodied energy of material, it was seen that brick had the major contribution in embodied energy of the building. Brick can be replaced by materials having lower embodied energy like Concrete Masonry units or Stabilised Earth Blocks. Therefore, it is the duty of the architect or the engineer to choose the materials with lower energy values and also make their clients aware of the energy savings that can be done.

Embodied Energy share of Building Envelope Material 2% 1%

Brick Plaster Paint

27%

40%

Glass Timber

Concrete

15%

Steel

11% 1%

0%

Bitumen

3%

Clay tiles

Figure 7.3: Embodied energy share of building envelope material. Source: Author.

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Insulation 7500000

7000000

6500000 Roof Wall

6000000

5500000

5000000

Uninsulated

1 inch

2 inch

3 inch

4 inch

Figure 7.4: : Variation of operational energy with insulation. Source: Author.

On the application of polystyrene insulation of various thicknesses to roof and walls, we noticed that though there is little reduction in the operational energy when the roof is insulated, there is significant saving when the walls are insulated. From the graph, we also infer that on initially adding insulation to the envelope, there is a drastic reduction in the operational energy; however, as we keep on increasing the insulation values, the effect of insulation keeps on reducing.

Net savings in energy in case of roof insulation is up to 3% whereas in case of wall insulation, the saving is up to 18%.

Various Changes in Envelope On application of various elements in the buildingâ€&#x;s envelope, it is seen that initially the operational energy changes significantly, however, with increasing variation, there is little change and the operational energy tends to remain constant.

The maximum fall in operational energy occurs during the change from single to double glazing and then to reflective glazing as double glazing creates insulating effect and reflective glass reflects most of the solar heat gain. Therefore, it is advisable for hotel designers to employ double reflective glazing in their hotel facades to substantially reduce the energy costs.

Also, application of too much elements altogether will not create that much effect as seen from the graph, and will only result in the increase of embodied energy and costs.

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Operational Energy 8000000 7000000

Energy(MJ)

6000000 5000000 4000000 3000000 2000000

Operational Energy

1000000 0

Figure 7.5: Variation of operational energy with variations in envelope. Source: Author.

7.2 Recommendations for Architects/Designers/Engineers: With increasing importance of green practices and energy efficiency in buildings today, the role of the architect does not limit to the designing of the structure only but also making it more sustainable.

Therefore, it is the duty of the architect/engineer to employ energy efficient measures in the building and also make their clients aware of the energy and cost savings that can be done. The following is the list of recommendations for architects/designers/engineers: 

In the hotel industry, much of the thought about the building‟s envelope is placed on the exterior aesthetics only with the attention often being focused on products and systems installed inside the building. Therefore, attention should also be paid on making the envelope energy efficient.



A database of all the low embodied energy materials should be prepared along with the specifications prior to the construction to be used in the building.



The form and orientation of the building should only be finalized after it has been undergone energy modelling and life-cycle analysis to optimize the performance of all components of the building envelope.



The local climatic conditions should be considered so as to know the most suitable materials in the construction of the envelope and the amount of and performance of glazing to be used specific to each orientation, and the overall energy performance of the building.

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

Optimal insulation should be employed in the envelope‟s opaque elements so as to cater to both heating and cooling seasons.



Use of shading devices such as vertical fins and overhangs and day lighting controls is advisable but only to a certain extent otherwise it will only increase the costs with little reduction in the overall energy.



Each building‟s Net Global Warming Potential should be calculated and mentioned on plans that go for approval. The approval should also take place through Department of Energy which should set a maximum limit for the same.

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BIBLIOGRAPHY Indexing of Building Materials with Embodied, Operational Energy and Environmental Sustainability with Reference to Green Buildings. (2012). Ashok Kumar; D. Buddhi; D. S. Chauhan, 11-22.

Alcorn, A. (2001). Embodied energy and CO2 coefficients for Nz building materials. Centre for Building Performance Research.

Blanchard, S., & Reppe, P. (1998). Life cycle analysis of a residential home in Michigan.

Chen, J. (2009). Advances in Hospitality and Leisure. Emerald Group Publishing.

Cleveland, C. J., & Morris, C. G. (2009). Dictionary of Energy. Elsevier.

Congress, I. B. (2008). Energy Conservation in Buildngs. New Delhi: Nabhi Publications.

Grondzik, W. T., Kwok, A. G., Stein, B., & Reynolds, J. S. (2011). Mechanical and Electrical Equipment for Buildings. New Jersey: John Wiley & Sons.

Harvey, D. (2012). A Handbook on Low-Energy Buildings and District-Energy Systems: Fundamentals, Techniques and Examples. New York: Routledge.

Harvey, D. (2013). Energy and the New Reality 1 - Energy Efficiency and the Demand for Energy Services. New York: Routledge.

Hsu, S. L. (2009). Life Cycle Assessment of Materials and Construction .

Joseph Chen, P. S. (2010). Eco-advantage in the Hospitality Industry. Routledge.

Kulkarni, V., & Ramachandra, T. V. (2006). Environmental Management. New Delhi: TERI Press.

Lee, S. H., Jain, L. C., & Howlett, R. J. (2009). Sustainability in Energy and Buildings. Springer Science & Business Media.

Lovel, J. (2013). Building Envelopes: An Integrated Approach. New York: Princeton Architectural Press.

Majumdar, M. (2001). Energy-efficient Buildings in India. New Delhi: TERI Press.

Philip Sloan, W. L. (2013). Sustainability in the Hospitality Industry: Principles of Sustainable Operations. Routledge.

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Praseeda, K. I., M. M., & Reddy, B. V. (2013). Assessing impact of material transition and thermal comfort models on embodied and operational energy in vernacular dwellings (India).

ScienceDirect, 342-351.

Punmia, B., Jain, A. K., & Jain, A. K. (2005). Building Construction. New Delhi: Firewall Media.

Richard H. Penner, L. A. (2013). Hotel Design, Planning and Development. New York: Routledge.

Sustainability in Hotel and Hospitality Design. (n.d.). Retrieved August 4, 2014, from Linedota: http://www.linedota.com/sustainable-hotels/ Tillotson, G. H. (2006). Jaipur Nama: Tales from the Pink City. New Delhi: Penguin Books India.

Utama, A., & Gheewala, S. H. (2006). Embodied Energy of Building Envelopes and its Influence on Cooling Load in Typical Indonesian Middle Class Houses .

Zelenay, K., Perepelitza, M., & Lehrer, D. (2011). High-Performance Facades: Design Strategies and Applications in North America and Northern Europe. Berkeley: Center for the Built Environment.

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APPENDIX 1: LIST OF EMBODIED ENERGIES OF COMMON MATERIALS Material Aggregate, general virgin rock river Aluminium, virgin extruded extruded, anodised extruded, factory painted foil sheet Aluminium, recycled extruded extruded, anodised extruded, factory painted foil sheet asphalt (paving) bitumen brass Carpet felt underlay nylon polyester polyethylterepthalate (PET) polypropylene wool Cement cement mortar fibre cement board soil-cement Ceramic brick brick, glazed pipe tile Concrete block brick GRC paver pre-cast ready mix, 17.5 MPa

MJ/kg 0.1 0.04 0.02 191 201 227 218 204 199 8.1 17.3 42.9 34.3 20.1 14.8 3.4 44.1 62 72.4 18.6 148 53.7

MJ/m3 150 63 36 515 700 542 700 612 900 588 600 550 800 537 300 21 870 46 710 115 830 92 610 54 270 39 960 7 140 45 420 519 560

MJ/m2

107 95.4 106 7.8 2 9.5 0.42 2.5 7.2 6.3 2.5 0.94 0.97 7.6 1.2 2 .0 1

15 210 3 200 13 550 819

102/7.5mm

5 170 14 760 5 250

14 820

2 350

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30 MPa 40 MPa roofing tile copper Earth, raw adobe block, straw stabilised adobe, bitumen stabilised adobe, cement stabilised rammed soil cement pressed block Fabric cotton polyester Glass float toughened laminated tinted Insulation cellulose fibreglass polyester polystyrene wool (recycled) lead linoleum Paint solvent based water based Paper building kraft recycled wall plaster, gypsum plaster board Plastics ABS high density polyethelene (HDPE) low density polyethelene (LDPE) polyester polypropylene polystyrene, expanded

1.3 1.6 0.81 70.6

3 180 3 890 631 160

0.47

750

0.29 0.42 0.8 0.42 143 53.7 15.9 26.2 16.3 14.9

40 060 66 020 41 080 375 450

3.3 30.3 53.7 117 14.6 35.1 116 90.4 98.1 88.5 36.4 25.5 12.6 23.4 36.4 4.5 6.1

112 970 430 2 340 139 398 030 150 930 118/l 128/l 115/l 33 670

240/6mm 396/6mm 246/6mm

337 6.5 6.1 7.4 4.97

6 460 5 890

33/9.5mm

111 103

97 340

103

91 800

53.7 64 117

7 710 57 600 2 340

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polyurethane PVC Rubber natural latex synthetic sand Sealants and adhesives phenol formaldehyde urea formaldehyde Steel, recycled reinforcing, sections wire rod Steel, virgin, general galvanised imported, structural Stone, dimension local imported straw, baled Timber, softwood air dried, roughsawn kiln dried, roughsawn air dried, dressed kiln dried, dressed mouldings, etc hardboard MDF glulam particle bd plywood shingles Timber, hardwood air dried, roughsawn kiln dried, roughsawn vinyl flooring Zinc galvanising, per kg steel

74 70

44 400 93 620

67.5 110 0.1

62 100 232

87 78.2 10.1 8.9 12.5 32 34.8 35

251 200 273 180 274 570

0.79 6.8 0.24

1 890 1 890 30.5

0.3 1.6 1.16 2.5 3.1 24.2 11.9 4.6 8 10.4 9

165 880 638 1 380 1 710 13 310 8 330 2 530

0.5 2 79.1 51 2.8

388 1 550 105 990 364 140

37 210

15.2

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