Analysis of Building Envelops to Optimize Energy...

Master of Science Thesis

KTH School of Industrial Engineering and Management

Energy Technology EGI-2012-70MSC

Division of xxx

SE-100 44 STOCKHOLM

Analysis of Building Envelops to

Optimize Energy Efficiency as per

Code of Practice for Energy Efficient

Buildings in Sri Lanka -2008

Epa Arachchillage Ushani Chamikala Epa

Kumari

i

Master of Science Thesis EGI-2012-70MSC

Analysis of Building Envelops to Optimize Energy

Efficiency as per Code of Practice for Energy

Efficient Buildings in Sri Lanka -2008

Epa Arachchillage Ushani Chamikala Epa Kumari

Approved

Examiner

Dr. Jaime Arias

Supervisor

KTH: Dr. Jaime Arias

OUSL: Prof. Rahula

Attalage

Commissioner

Contact person

Abstract

Residential and commercial buildings consume approximately 20% of the global energy generation. This

value is continuously growing and the governments across the globe have realized the importance of

regulating the building construction to optimize the energy utilization. Energy efficient building codes

have been developed to optimize the energy efficiency in buildings. OTTV (Overall Thermal Transfer

Value) is a key parameter for evaluating energy efficiency of building envelops in the present building code

of Sri Lanka. In this research, the prescriptive requirements mentioned in the building code for the

building envelops to optimize the energy efficiency of five (05) commercial buildings has been analyzed.

The indoor climate was modeled and the annual cooling energy variation with Overall Thermal Transfer

Value was studied using “DesignBuilder” software. A cost benefit analysis was carried out for enhanced

energy efficiency building envelops applications. It was attempted to develop a general relationship

between the OTTV and annual cooling energy requirement for each building. It has been observed that a

second order polynomial relationship with R2 of 0.861 exists for RDA building, linear relationship with R2

of 0.838 exists for AirMech building. However a specific relationship could not be observed for BMICH,

SLSI and WTC buildings. The impact on cooling energy requirement from envelop parameter

modification is unique for each building. In some instances the reduction of OTTV has not resulted in

any reduction of the cooling energy requirement. There is a combined effect from each building

component which affects the final cooling energy requirement. A simulation based technique to be used

to find the optimum building envelops design.

ii

Table of Contents

1 Introduction ............................................................................................................................... 1

1.1 Background .................................................................................................................................................. 1

1.2 Problem statement ...................................................................................................................................... 2

1.3 Objectives ..................................................................................................................................................... 3

2 Literature Review ....................................................................................................................... 4

2.1 History of building codes in the world .................................................................................................... 4

2.2 Types of regulations.................................................................................................................................... 4

2.2.1 Prescriptive type regulations ............................................................................................................ 4

2.2.2 Trade-off type regulations ................................................................................................................ 5

2.2.3 Model building type regulations ...................................................................................................... 5

2.2.4 Energy frame type regulations ......................................................................................................... 5

2.2.5 Performance type regulations .......................................................................................................... 5

2.3 Code of Practice for Energy Efficient Buildings in Sri Lanka – 2008 ................................................ 6

2.3.1 External wall with/without Fenestration (Facades) ...................................................................13

2.3.2 Roofs ..................................................................................................................................................13

2.3.3 Area Weighted Cumulative Overall Thermal Transfer Value (OTTV) ..................................14

2.4 Introduction of OTTV as a building code parameter .........................................................................15

2.5 Previous studies on OTTV ......................................................................................................................15

2.6 Overview of DesignBuilder software as a simulation tool .................................................................16

3 Methodology ............................................................................................................................ 18

3.1 Identification of five (05) office buildings in Colombo, Sri Lanka ...................................................18

3.2 Collection of data for calculation of the building envelop properties ..............................................19

3.3 Modeling of indoor climate .....................................................................................................................19

3.3.1 Building 1: Project Office of Greater Colombo Urban Transport Development Project ...21

3.3.2 Building 2: Wing 4 G of Bandaranayke Memorial International Conference Hall ...............24

3.3.3 Building 3: Air- Mech Engineering Office ...................................................................................27

3.3.4 Building 4: Sri Lanka Standards Institute (SLSI) ........................................................................30

3.3.5 Building 5: World Trade Centre (WTC) .......................................................................................34

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4 Analysis of Results ................................................................................................................... 37

4.1 Analysis of Simulation Results ................................................................................................................37

4.2 Cost benefit analysis for enhanced energy efficiency building envelops applications ...................38

4.2.1 Building 1 (RDA) .............................................................................................................................39

4.2.2 Building 2 (BMICH) ........................................................................................................................40

4.2.3 Building 3 (Air-Mech) .....................................................................................................................41

4.2.4 Building 4 (SLSI) ..............................................................................................................................42

4.2.5 Building 5 (WTC) .............................................................................................................................43

4.3 Summary of the optimum building envelops models .........................................................................43

5 Discussion and Conclusion ..................................................................................................... 45

6 Bibliography ............................................................................................................................ 49

ANNEXURE 1: Calculation of OTTV and annual cooling energy of buildings………………………...51

ANNEXURE 2: Cost of Building Materials …………………………………………………………..106

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Index of Tables

Table 2-1: Maximum U-values for facades with or without fenestration ............................................................................13 Table 2-2: Maximum U-Factor values for roofs ...............................................................................................................14 Table 3-1: Assumptions and data used for buildings simulation .......................................................................................20 Table 3-2: Absolute and percentage reduction of OTTV and annual cooling energy with modifications of building 1 .........23 Table 3-3: Absolute and percentage reduction of OTTV and annual cooling energy with modifications of building 2 .........26 Table 3-4: Absolute and percentage reduction of OTTV and annual cooling energy with modifications of building 3 .........29 Table 3-5: Absolute and percentage reduction of OTTV and annual cooling energy with modifications of building 4 .........32 Table 3-6: Absolute and percentage reduction of OTTV and annual cooling energy with modification of building 5 ...........35 Table 4-1: Building modifications resulted to increase of annual cooling energy ...................................................................37 Table 4-2: Relationship between OTTV and annual cooling energy ..................................................................................37 Table 4-3: LCC for different modifications of building 1 ..................................................................................................39 Table 4-4: LCC for different modifications of building 2 ..................................................................................................40 Table 4-5: LCC for different modifications of building 3 ..................................................................................................41 Table 4-6: LCC for different modifications of building 4 ..................................................................................................42 Table 4-7: LCC for different modifications of building 5 ..................................................................................................43 Table 4-8: Recommended modification for buildings ..........................................................................................................43 Table 5-1: Variation of OTTV and specific annual cooling energy requirement with modification for buildings .................45

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Index of Figures

Figure 1-1: Share of electricity consumption in Sri Lanka .................................................................................................. 1 Figure 2-1: Exterior and semi-exterior building envelop ..................................................................................................... 7 Figure 2-2: Schematic showing three modes of heat transfer of an exterior envelop element .................................................... 7 Figure 2-3: Nomenclature for conduction in plane walls ...................................................................................................... 8 Figure 2-4: Thermal radiation effects of wall .....................................................................................................................10 Figure 2-5: Climatic zones of Sri Lanka .........................................................................................................................12 Figure 2-6: Input/output to the DesignBuilder software ...................................................................................................17 Figure 3-1: Layout diagram of the existing building 1 ......................................................................................................22 Figure 3-2: Variation of the annual cooling energy with the OTTV of the building 1 .......................................................24 Figure 3-3: Layout diagram of the existing building 2 ......................................................................................................25 Figure 3-4: Variation of the annual cooling energy with the OTTV of the building 2 .......................................................27 Figure 3-5: Layout diagram of the existing building 3 ......................................................................................................28 Figure 3-6: Variation of the annual cooling energy with the OTTV of the building 3 .......................................................30 Figure 3-7: Layout diagram of the existing building 4 ......................................................................................................31 Figure 3-8: Variation of the annual cooling energy with the OTTV of the building 4 .......................................................33 Figure 3-9: Variation of the annual cooling energy with the OTTV of the building 4 (after removing two data points) ......33 Figure 3-10: Layout diagram of the existing building 5 ....................................................................................................34 Figure 3-11: Variation of the annual cooling energy with the OTTV of the building 5 .....................................................35 Figure 3-12: Variation of the annual cooling energy with the OTTV of the building 5(after removing two data points) .....36 Figure 5-1: Variation of specific annual energy consumption Vs OTTV for buildings ......................................................46

vi

Nomenclature

OECD Organization for Economic Cooperation and Development SLSEA Sri Lanka Sustainable Energy Authority

U.S United Status

OTTV Overall Thermal Transfer Value W/m2

U Overall heat transfer Coefficient W/m2.0C

R Unit thermal resistance m2.0C/W

CEB Ceylon Electricity Board

EEBC Code of Practice for Energy Efficient Buildings in Sri Lanka 2008

ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers

IHG Internal Heat Gains

DLG Double Layer Glazing

LKR Sri Lankan Rupees

1

1 Introduction

This chapter provides an introduction to the research. There are three subsections to this introduction,

namely; background, problem statement and objectives. The background section describes the global

energy utilization in building sector and importance of the energy efficient building regulations. The

problem statement focuses some issues identified in the “Code of Practice for Energy Efficient Buildings

in Sri Lanka -2008”. The objectives of the research scope are mentioned in the third part.

1.1 Background

According to the International Energy Outlook 2010, residential and commercial buildings consume

about one fifth of the world’s total energy delivered. It is projected that the energy need growth rate

among residential and commercial sector of non-OECD nations from 2007 to 2035 are 1.9 percent per

year and 2.7 percent per year respectively [U.S. Energy Information Administration, 2010]. In both these

sectors energy goes for the building systems of different nature. This includes energy used for controlling

the climate in buildings, energy used for appliances, lighting and other installed equipment.

As far as the national level electricity consumption is concerned, the use of electricity in buildings

accounts for a large share of the total national energy consumption. Commercial sector, under which large

scale buildings are there, contributes to 24% of the consumption, and the consumption of the domestic

sector is 40% .Total annual electricity consumption in 2010 is 9208 GWh [Sri Lanka Sustainable Energy

Authority, 2010].

Figure 1-1: Share of electricity consumption in Sri Lanka (Sri Lanka Sustainable Energy Authority, 2010)

Building materials and technologies, and building practices have evolved through ages. Housing and

building conditions reflect the living standards of the society. People spend significant amount of time of

Domestic40%

Industrial34%

Commercial24%

Religious1%

Street lighting1%

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their life in indoors and the condition of the built environment mainly affect to the comfort, health and

productivity of occupants.

In a large scale building, air conditioning is the highest share of electricity load and lighting also

contributes to a significant portion. A significant amount of energy wasted due to the inefficient design,

equipments and inappropriate behavior of occupants.

As such, in the light of the current energy crisis, any positive changes in this sector targeting the efficient

use of energy would have a significantly positive impact on the overall energy consumption of the country.

Buildings are designed for many decades and inefficient buildings consume more energy basically for

space conditioning and lighting. It has been realized that the life cycle cost of a building can be drastically

reduced through better planning and designing. Introduction of energy efficient measures during initial

state may involve no or least cost as an example consideration of building orientation, size and orientation

of windows, selection of construction materials, introduction of natural ventilation and passive design

techniques, installation of efficient equipments etc. But it reduces the lighting, ventilation and cooling or

heating energy during operation. Improvement of energy efficiency of a building at the planning stage is

relatively simple and cost effective while improvements after the construction are much more difficult.

Building codes or energy standards introduce minimum energy performance standards for new buildings

and retrofits. Energy efficiency requirements in building codes or energy standards for new buildings are

therefore among the most important single measures towards improving energy efficiency.

1.2 Problem statement

Code of Practice for Energy Efficient Buildings in Sri Lanka – 2008 has introduced by the Sri Lanka

Sustainable Energy Authority (SLSEA) in year 2009. It has defined the minimum energy performance

standards under five elements namely; lighting, ventilation and air conditioning systems, building envelops,

service and water heating and electrical power distribution [Sri Lanka Sustainable Energy Authority, 2009].

At the moment the Code is in implementation phase and it is practiced by professionals and building

constructors in voluntary basis. Although the SLSEA has defined these minimum energy performance

values, those have not been verified yet.

Building envelop refers to the external elements of the building namely roof, wall, floors and fenestration.

External heat gains and losses of the building are occurred through the envelop. Therefore the properties

of the envelop materials directly affect to the thermal and visual comfort of the occupants as well as the

energy consumption of the building. The building envelop is one of the major element which has huge

potential to reduce the life cycle cost by proper design during the design phase. This research is focused in

finding solutions to following problems of building envelop section of the Code.

1. The impact of the minimum energy performance standards (prescribed in the building code for the

building envelops) to the building energy efficiency has not been verified.

2. The incremental cost benefit of prescriptive parameters vs energy efficiency has not been quantified.

3. There is no general guideline /grading system for building envelops design based on energy efficiency.

3

1.3 Objectives

The objectives of the research are as follows. These objectives were defined with the view of limiting the

scope of the research to achieve specific target within the available time and resources.

1. Analyze the prescriptive requirements mentioned in the building code for the building envelops to

optimize the energy efficiency of commercial buildings.

2. Modeling of indoor climate and study the cooling energy variation with Overall Thermal Transfer

Value, using “DesignBuilder” software.

3. Carry out a cost benefit analysis for enhanced energy efficiency building envelops applications.

4. Provide general guidelines / recommendations for building envelop design which could be useful to

policy makers.

This chapter provided an introduction to the research project including background, problems to be

solved in this research and the objectives.

4

2 Literature Review

This chapter covers the literature review carried out as a part of the research. The objective of the

literature review was to obtain an in depth understanding of the previous studies carried out in this subject

area. This chapter includes history and overview of the building codes in the world, types of regulations

used for improvement of energy efficiency in buildings, introduction of a code of practice for energy

efficient buildings in Sri Lanka, overview of overall thermal transfer value and overview of the

“DesignBuilder” software.

2.1 History of building codes in the world

Building codes or standards are used from several years ago addressing mainly the occupants' health and

safety. First introduction of insulation requirements for U values, R values and specific insulation

materials or multi glazing was in Scandinavian countries in late 1950s. But in many countries energy

efficient building codes has been introduced and used, specially during the oil crisis in 1970s. [Jens

Laustsen, 2008].

Some of the examples for energy codes available in the world;

1. America - ANSI/ASHRAE/IESNA Standard 90.1-2004 “Energy Standard for Buildings Except

Low-Rise Residential Buildings”

2. Malaysia – Code of Practice on Energy Efficiency and Use of Renewable Energy for Non-

Residential Buildings

3. Philippines – The National Building Code of Philippines

4. India – Energy Conservation Building Code

2.2 Types of regulations

There are different types of energy efficiency regulations which are used in the building codes. Each type

use different approach to achieve the ultimate objective of energy conservation. Basic types are as follows;

1. Prescriptive

2. Trade-off

3. Model building

4. Energy frame

5. Performance

2.2.1 Prescriptive type regulations

In this method, energy efficiency requirements are set for each building part and each part of the

equipment system. As an example, it sets thermal transfer value (U values) or thermal resistance value (R

values) for each element of the building envelop, visual transmittance values for fenestrations, the number

and size of windows or window to wall ratio, coefficient of performance of air conditioners, pumps, fans

etc. In the prescriptive method, it is required to meet each and every individual component with its

specific value [Jens Laustsen, 2008].

5

2.2.2 Trade-off type regulations

In trade-off method it is sets energy efficiency requirements for each component of the building as similar

to the prescriptive method. But there is flexibility to trade-off between different components, so some

values are better and some are worse than the requirements [Jens Laustsen, 2008].

2.2.3 Model building type regulations In this method, it sets the energy efficiency values for each building part and each part of the equipment.

According to the clearly defined calculation method, a building model is developed with the same shape

and characteristics of the actual building are calculated with the energy efficiency set values. Then the

characteristic of the actual building is calculated with the actual values for the individual building parts and

systems, following the same calculation method. Finally the results of the calculation of two buildings are

compared and the actual building must perform as well or better than the model building.

This method offer more freedom and flexibility than prescriptive method. It can replace expensive

systems with more cost effective energy efficient techniques [Jens Laustsen, 2008].

2.2.4 Energy frame type regulations

In Energy Frame method, the overall performance of the building is considered rather than the

performance of individual elements. It sets the values for a building’s maximum energy loss. This is

usually set as a value per m² of building area or as a combination. The building energy loss is calculated

using U-values, temperature, surface and heat gains from sunlight etc according to the specified methods

and set of equations. This method offers the freedom to builder to build parts of the buildings that are

less energy efficient when other parts are made better than typical constructions. As long as the overall

value is met, the building is approved [Jens Laustsen, 2008].

2.2.5 Performance type regulations

In energy performance method, a total requirement for the building is set based on a building’s overall

consumption of energy or fossil fuel or the building’s implied emissions of greenhouse gas. This is usually

set as an overall value, consumption per m² of building area or a mixture, for different types of use or

different types of buildings etc.

The calculations are much comprehensive and it is required to use an advanced computer based model,

which integrate all the different parts and installations of the building. In the energy performance, it is

required to consider the installations of renewable energy, solar gains, recovery of energy losses, shading

and efficiency in installations for energy consumption calculation. Consumption of fossil fuel, building’s

implied emission is calculated comparing the use of different energy forms depending on local energy

conditions.

This method gives optimal freedom for constructors or designers to reduce energy consumption within

the frame by using alternatives [Jens Laustsen, 2008].

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2.3 Code of Practice for Energy Efficient Buildings in Sri

Lanka – 2008

The history of the energy efficient building codes in Sri Lanka runs back to year 2000. Realizing the

pressing need for the revitalization of building design in the country, Ceylon Electricity Board (CEB)

developed an Energy Efficient Building Code (EEBC) way back in 2000. Unfortunately, as the actual

implementation of the code was on voluntary basis, it did not get off the ground.

Given this background, and the need for building codes to be continuously upgraded in the face of

advancing technological innovations, Sri Lanka Sustainable Energy Authority reviewed the Energy

Efficient Building Code and published the document of Code of Practice on Energy Efficient Buildings in

Sri Lanka - 2008.

Code of Practice for Energy Efficient Buildings encourages energy efficient designs and retrofits of

buildings to reduce energy consumption without compromising the function of the building, or the

comfort, health and productivity of occupants. It sets minimum energy performance standards for

buildings and at the same time provides the methods for determining compliance. The Code is applicable

to commercial buildings, industrial facilities and large scale housing complexes that have at least one of the

features namely; four or more floors, a floor area of 500 m2 or more, an electricity demand of 100 kVA or

more and an air conditioning capacity of 350 kW or more. It has been developed to cover the building

elements; building envelops, ventilation and air conditioning systems, lighting, service and water heating

and electrical power distribution [Sri Lanka Sustainable Energy Authority, 2009].

In this research it is focused on the building envelop section only. According to the building code [Sri

Lanka Sustainable Energy Authority, 2009], “Building envelope refers to the exterior plus the semi-

exterior portions of a building. For the purposes of determining building envelope requirements, the

classifications are defined as follows:

(a) Building envelope, exterior: the elements of a building that separate conditioned spaces from the

exterior

(b) Building envelope, semi-exterior: the elements of a building that separate conditioned space from

unconditioned space or that encloses semi-cooled spaces through which thermal energy may be

transferred to or from the exterior, or to or from unconditioned spaces, or to or from conditioned spaces”

.

7

Figure 2-1: Exterior and semi-exterior building envelop (American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2004)

Building envelope elements play a considerable role on the visual and thermal comfort of the occupants

and energy consumption of the building. By proper design and construction of the building envelop the

load on these systems can be reduced. Heat transmission of a building is occur through the components

of the building envelop. Generally heat is transferred from high temperature to low temperature. The

three-ways of heat transfer namely; conduction, convection and radiation are occurred in simultaneously

in a building. Conduction is the transfer of heat in a solid medium due to the direct contact of particles.

Convection heat transfer occurs due to the movement of a fluid. Radiation heat transfer is the movement

of energy/heat through space without relying on conduction through the air or by the movement of air.

Figures 2.2 indicate these three-modes of heat transfer occurred in external surfaces of a building.

Figure 2-2: Schematic showing three modes of heat transfer of an exterior envelop element (Bureau of Energy Efficiency,2009)

8

The conductive heat transfer of the envelop element depend on the properties such as thermal

conductivity, density and thickness of the construction material.

The steady-state conduction in one dimension is given by Fourier’s Law of Conduction;

dx

dtkAq

.

(2.1)

Where;

.

q = rate of heat transfer [W]

k = thermal conductivity of the material [Wm2.C-1]

A = area normal to heat flow [m2]

dx

dt = temperature gradient [C/m]

Equation 2.1 incorporates a negative sign because q.

flows in the positive direction of x when dx

dt is

negative.

Figure 2-3: Nomenclature for conduction in plane walls (Faye C. McQuiston, Jerald D. Parker and Jeffrey D. Spitler, 2005)

Considering the flat wall of Figures 2.3 (a), where uniform temperature t1 and t2 are assumed to exist on

each surface. If the thermal conductivity, the heat transfer rate, and the area are constant, Equation 2.1

may be integrated to obtain;

Thermal resistance 𝑅′, is proportional to the material thickness and inversely proportional to the material

conductivity.

kA

x

kA

xxR

)(' 21 (2.2)

k1 k3 k2

x2 –x1

k

x

t1 t2

(a)

x

t1 t2

∆x1 ∆x3 ∆x2

(b)

9

The thermal resistance for a unit area is defined by;

k

xR

(2.3)

The thermal resistance 𝑅′, q and (t2-t1) are analogous to electrical resistance, current and potential

difference in Ohm’s law. This analogy can be used to analyze the conduction heat through a wall, roof

and windows made up of two or more layers of dissimilar materials. Figures 2.3 (b) shows a wall

constructed of three different materials. The heat transfer by conduction is given by;

Ak

x

Ak

x

Ak

xRRRR

3

3

2

2

1

1'

3

'

2

'

1

'

(2.4)

Where; the resistances are in series.

Thermal conductance C of the material is given by;

x

k

RC

1 (2.5)

Heat transfer rate due to the thermal convection is given by;

)(.

wtthAq (2.6)

Where;

h = film coefficient, [Wm-2.K-1]

t = bulk temperature, [0C]

tw = wall temperature, [0C]

Equation 2.6 can also be expressed in terms of thermal resistance for convection 𝑅𝑐𝑛𝑣′ ;

'

.

cnv

w

R

ttq

(2.7)

Where hA

Rcnv

1' (2.8)

Therefore convection thermal resistance for unit area, 𝑅𝑐𝑛𝑣

hR cnv

1 (2.9)

The film coefficient h depends on the fluid, the fluid velocity, the flow channel or wall shape or

orientation, and the degree of development of the flow field. There are two types of convection

mechanisms called forced convection and free or natural convection. When the convection heat transfer is

occurred due to the movement of bulk of fluid relative to the heat transfer surface, the mechanism is

10

called forced convection. Usually the motion is caused by a blower, fan or pump. Here the effects of the

buoyancy forces are negligible. The free convection is occurred due to the movement of fluid due to the

buoyancy forces. The surrounding bulk of the fluid is stationary and exerts a viscous drag on the layer of

moving fluid(Faye C. McQuiston, Jerald D. Parker and Jeffrey D. Spitler, 2005).

The direct net transfer of energy by radiation between two surfaces that see only each other and that are

separated by a nonabsorbent medium is given by;

22

2

121

1

11

1

4

2

4

112

.

111

)(

AFAA

TTq

(2.10)

Where;

= Boltzmann constant = 5.673 x 10-8 [W/m2.K4]

T = absolute temperature [K]

= emittance of surface 1 or surface 2

A = surface area [m2]

F = configuration factor, a function of geometry only

(Faye C. McQuiston, Jerald D. Parker and Jeffrey D. Spitler, 2005)

In equation 2.10, it is assumed that emittance ( ) equals to absorptance ( ) in both surfaces.

Figure 2-4: Thermal radiation effects of wall (Faye C. McQuiston, Jerald D. Parker and Jeffrey D. Spitler, 2005)

Considering the wall at Figures 2.4

....

orwi qqqq (2.11)

For the wall being heated by a combination of convection and radiation on each surfaces and having 5

different resistances, the equivalent thermal resistance '

eR

qr

qw

t0

h0

ti

hi k

qi

q0

11

''

3

'

2

'

1

''

oie RRRRRR (2.12)

In terms of fundamental variables;

OOii

eAhAk

x

A

R

Ak

x

AhR

11

33

3

2

2

11

1'

(2.13)

Overall heat-transfer coefficient is given by;

RAR

U11

/ (2.14)

The heat transfer rate in each component is given by;

tUAq .

(2.15)

Where;

UA = conductance [W/C]

A = Surface area normal to flow [m2]

t = overall temperature difference [C]

The rate of heat transfer proportional to the overall heat transfer coefficient, surface are normal to flow

and overall temperature difference. Therefore the rate of heat transfer of the element can be reduced by

increasing the thermal resistance. In order to increase the resistance it can introduce low conductive

materials and or increase the thickness of the material layers.

The average yearly temperature of Sri Lanka ranges from 280C to 320C. The difference of elevation in Sri

Lanka influences temperature variation in the country. It ranges from hot to cold from the lowland to

upland. According to the Department of Agriculture, Sri Lanka can be divided in to three climate zones

namely wet, intermediate and dry zone and Figures 2.5 indicates the zones.

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Figure 2-5: Climatic zones of Sri Lanka (http://www.climatechange.lk/maps/climaticzones.jpg)

The thermal properties of the building depend on its outdoor climate conditions as well as the internal

conditions such as type of the activities, time of operation. In the Code, the country is divided in to three

climatic zones, namely warm-humid, warm-dry and uplands based on the outdoor dry bulb and wet bulb

temperatures. These represent the climate zones wet, intermediate and dry in Figures 2.5 respectively. The

specified dry bulb and wet bulb temperatures of different zones are;

Warm-humid – 310C, 270C

Warm-dry – 330C, 260C

Uplands – 280C, 230C

Based on the duration of the operation of the building two typologies are identified as day-time operation

and extended operation. Normal eight (08) hours per day operation buildings such as offices, shops are

considered as day time operation and more than 08 hour operation buildings such as hospitals, hotels, and

supermarkets are considered as extended operation. The materials to be used in the construction are

decided according to the climatic zone as well as building typology.

13

The code specifies the prescriptive requirement limits for physical properties such as Visual Light

Transmittance, U value, solar absorpsivity of materials used for roofs, fenestrations and facades elements

as follows,

2.3.1 External wall with/without Fenestration (Facades)

2.3.1.1 Visual Light Transmittance (VLT)

Visual light transmittance is the measure of the percentage of visible light that passes through the glazing

material. VLT of the glass is influenced by the colour of the glass, coatings on the glass, type of the glass

etc. The higher the number, the more visible light transmitted. A lower VLT rated glasses are used to

minimize the glare, while a higher VLT rated glasses are used to maximize natural light (Efficient windows

collaborative, http://www.efficientwindows.org/vt.cfm).

In order to comply with the Building Code the mean visual light transmittance for all fenestrations shall be

greater than 0.15

2.3.1.2 Overall heat transfer coefficient (U) values

The code sets the maximum limits for U values for facades according to the climate zone and operation

time of the building. Based on the outdoor dry bulb and wet bulb temperatures, three climatic zones,

namely warm-humid, warm-dry and uplands are specified. Based on operating hours, two categories as

day-time operation (08 hours operation) and extended operation (more than 08 hours operation) are

specified. Maximum U values are specified as follows;

Day-Time operation, (Wm-2K-1) Extended operation, (Wm-2K-1)

Warm-humid 0.45 0.40

Warm-dry 0.45 0.40

Upland 0.38 0.35

Table 2-1: Maximum U-values for facades with or without fenestration (Sri Lanka Sustainable Energy Authority, 2009)

2.3.2 Roofs

1.3.2.1 Solar absorpsivity

The solar absorptivity is the percent of incident solar radiation that is absorbed by the system. The lower

the number, the less solar radiation is absorbed.

In order to comply with the Building Code, the exterior roof surface solar absorptivity for non-tiled

roofing surfaces shall be less than 0.4.

14

1.3.2.2 Overall heat transfer coefficient (U) values

The code sets the maximum limits for U values for roofs according to the type of the roof, climate zone,

and operation time of the building as follows;

Day-Time operation, (Wm-2K-1) Extended operation, (Wm-2K-1)

Tiled Non-Tiled Tiled Non-Tiled

Warm-humid 0.30 0.40 0.30 0.28

Warm-dry 0.25 0.40 0.25 0.28

Upland 0.20 0.35 0.20 0.25

Table 2-2: Maximum U-Factor values for roofs (Sri Lanka Sustainable Energy Authority, 2009)

2.3.3 Area Weighted Cumulative Overall Thermal Transfer Value (OTTV)

According to the building code, “Area weighted cumulative OTTV of the actual building design

combining actual OTTVi values of all facades of the building and U-factor values of roofs shall be less

than the corresponding cumulative OTTV of the actual building design estimated using all prescriptive

values and also than a value of 50 W/m2” (Sri Lanka Sustainable Energy Authority, 2009).

This value represents the average rate of heat transfer through the building envelop due to the

temperature difference between exterior and the conditioned space. The OTTV is directly proportional to

the heat gain and the standards set the maximum OTTV for the building envelop. The aim of limiting the

OTTV is to reduce the heat gain and finally reduce the load on air conditioning.

𝑂𝑇𝑇𝑉 = 𝑄

𝐴

Where the terms defined as;

Q = Heat gain through the envelop (W)

A = Gross area of the building envelop (m2)

Heat gain through the envelop represents major three heat gains namely; Heat conduction through

opaque section of wall and roof , Heat conduction through fenestration and Solar heat gain through

fenestration.

𝑂𝑇𝑇𝑉𝑖 = ∆𝑇𝑒𝑞 ∝ 1 − 𝑊𝑊𝑅 𝑈𝑤 + ∆𝑇 𝑊𝑊𝑅 𝑈𝑓 + 𝑆𝐹 𝑊𝑊𝑅 𝑆𝐶 𝑆𝐹

𝑂𝑇𝑇𝑉 = 𝐴1𝑂𝑇𝑇𝑉1 + 𝐴2𝑂𝑇𝑇𝑉2 + 𝐴3𝑂𝑇𝑇𝑉3 …………… + 𝐴𝑁𝑂𝑇𝑇𝑉𝑁 + 𝐴𝑅𝑜𝑜𝑓𝑂𝑇𝑇𝑉𝑅𝑜𝑜𝑓

𝐴1 + 𝐴2 + 𝐴3 + …………… + 𝐴𝑁 + 𝐴𝑅𝑜𝑜𝑓

Where the terms are defined as:

15

OTTVi = Overall thermal transmittance value for the ith specific wall or roof orientation and construction

combination, (W/m2)

Ai = Area of the ith specific wall or roof (m2)

∆Teq = Equivalent indoor-outdoor temperature difference through the opaque wall section, (19.3°C)

= Solar absorptance of the exterior opaque wall (dimensionless)

WWR = Window-to-wall ratio, using the gross wall area in the denominator, (dimensionless).

Uw = Thermal transmittance of opaque wall section, (W/m2°C)

∆T = Temperature difference through the window section, (3.6°C)

Uf = Thermal transmittance of window section, (W/m2°C)

SF = Solar factor, defined as the average hourly value of solar energy incident on vertical windows, (186

W/m2)

SC = Shading coefficient of the fenestration system (dimensionless)

CF = Solar correction factor for the orientation of the fenestration

The Code has provided the respective constants for ∆Teq, ∆T, and SF and respective tables for CF and SC

by considering the Sri Lankan environmental conditions.

2.4 Introduction of OTTV as a building code parameter

The Overall Thermal Transfer Value (OTTV) is an index which was introduced by the American Society

of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) originated in 1975 to measure the

thermal performance of an air conditioned building by ASHRAE Standards 90-75, “Energy Conservation

in New Building Design”. Then many countries included this method for building codes [F.W.H Yik et al,

2005].

Later on, this method was dropped from ASHRAE standard 90.1-89 in favor of performance-based

energy budgets generated through computer simulations. But most of the Asian countries such as Hong

Kong, Singapore, Thailand, and Malaysia still use this method because of its relative ease of calculation,

and flexibility of trade-offs between different parts of the envelope.

2.5 Previous studies on OTTV

F.W.H Yik and K.S.Y Wan [F.W.H Yik et al, 2005] have carried out a research to study the

appropriateness of OTTV as a measurement to regulate the envelope energy performance of air

conditioned buildings. The research was carried out in Hong Kong. The research studies showed that for

16

buildings situated in a sub-tropical climate region like Hong Kong, “acceptable correlation between

OTTV and energy use for air-conditioning (with all other things being equal) could be achieved only if the

heat transfer in buildings during the cool months was ignored. Even though OTTV calculated in such a

way may be a good reflection of the impact of envelope performance on energy use for air-conditioning, it

remains an inadequate measure of the envelope performance” [F.W.H Yik et al, 2005].

Further they have questioned the appropriateness of pre calculated coefficients “As the case study results

for office and residential buildings presented in this paper show, the use of pre-calculated coefficients for

OTTV calculation has inherent deficiencies, as the interacting effects among heat gains from different

envelope elements and internal sources, and the impacts of room configuration cannot be properly

accounted for. The OTTV determined from such methods, therefore, is subject to uncertainties and may

be inconsistent with the envelope performance” [F.W.H Yik et al, 2005].

In order to increase the effectiveness they have suggested “To be effective, regulatory control over

building energy performance needs to include requirements on the energy performance of building

services installations. In order to provide designers with flexibility in meeting the control requirements in

the most economical manner, compliance through an alternative route that is based on the total energy

budget approach, as in ASHRAE Standard 90.1, should be provided”. One important suggestion provided

is “In this case, detailed computer simulation becomes an integral part of compliance demonstration.

When detailed simulation is used, minimum performance required of individual types of envelope

components can be specified on the basis of more basic characteristics, e.g. the characteristics of a

particular wall construction and glazing and a window-to-wall area ratio limit, instead of using the

simplistic OTTV method, which is prone to errors” [F.W.H Yik et al, 2005].

A research has been carried out in Malaysia by Mansour Nikpour et al, 2011 to study the Self shaded

strategy in high-rise buildings effect on minimizing the amount of OTTV. As per the research,” the

reduction is 68.94 × WWR for Malaysia. The effect of Self-shaded strategy is more significant if the

amount of WWR increase.

This is an effective approach to allow architectural design to have a more flexible building facade design,

and to enhance a more energy-efficient and greener building development.

2.6 Overview of DesignBuilder software as a simulation tool

DesignBuilder Version 2.4.2.010 was used for the modeling purpose. DesignBuilder is one of the

graphical user interfaces of Energyplus simulation engine. Energyplus is a building energy simulation

programme developed by U.S department of energy.

This software programme models energy flows such as heating, cooling, lighting, ventilation and water

use.

Capabilities of the DesignBuilder software version 2.4.2.010 are as follows;

Evaluating facade options for overhangs, internal blinds and visual appearance.

Thermal simulation of naturally ventilated buildings.

Daylighting - models lighting control systems and calculates savings in electric lighting.

Visualisation of site layouts and solar shading.

17

Calculating heating and cooling loads and required equipment sizes.

Limitations of the DesignBuilder software version 2.4.2.010 are as follows;

Version 2.4.2.010 is not capable of carrying out life cycle cost analysis.

It cannot analyze solar absorptivity and visual light transmittance parameters.

The input/output of the DesignBuilder software are as follows.

Figure 2-6: Input/output to the DesignBuilder software

Inputs

Location & Weather

data

Building Layout

Construction material

Building activities

Lighting

Openings

HVAC

Design Builder

Software

Outputs

Cooling Load

Heating Load

Simulation of build

environment with real weather

data

Energy consumption

Indoor climate condition

variations

System design load

18

3 Methodology

This chapter covers the methodology followed in the research. As explained in section 1.3, main

objectives of the research were to analyze the prescriptive requirements prescribed in the building code

for the building envelops to optimize the energy efficiency of commercial buildings, modeling of indoor

climate to study the cooling energy variation with Overall Thermal Transfer Value using “DesignBuilder”

software, carry out a cost benefit analysis for enhanced energy efficiency building envelops applications

and to provide general guidelines / recommendations for building envelop design which could be useful

to policy makers.

.

In the code, it has specified maximum allowable U-values for walls and roofs, air leakages for

fenestrations and doors, solar absorptivity for non-tiled roofing surfaces and minimum VLT for

fenestration under mandatory and prescriptive requirements. In order to comply with the Building Code,

it is required to meet all these requirements and the OTTV of the building should be less than the

corresponding cumulative OTTV of the building design estimated using all prescriptive values and also

than a value of 50W/m2.

With the time limitation, focus of this research was limited to analyze the improvements of energy

efficiency by means of annual cooling energy reduction of buildings with the OTTV reduction. The

selected buildings are located in warm-humid zone and operated in day time. The OTTV values of the

buildings were reduced by changing the U-values of walls, roof and fenestrations.

Below mentioned six basic steps were carried out during the research;

1. Identification of five (05) office buildings in Colombo.

2. Collection of data for calculation of the building envelop properties

3. Modeling of indoor climate and study the annual cooling energy variation with Overall Thermal

Transfer Value, using DesignBuilder software.

4. Carry out a cost benefit analysis for enhanced energy efficiency building envelops applications.

5. Identification of the optimum building envelops models.

6. Develop general guidelines /recommendations / grading system for building envelops design

based on the results.

3.1 Identification of five (05) office buildings in Colombo, Sri

Lanka

The code is applicable for the commercial buildings, industrial facilities and large scale housing

developments having one or more of the features; four or more stories, floor area of 500m2 or more,

electrical power demand of 100 kVA or more and air-conditioning cooling capacity of 350 kW (output) or

more. It defines maximum U values for facades and roofs according to the climate zone and building

usage.

The focus area of this research is limited to the day time operation buildings in warm humid climate.

Therefore 05 office buildings located in Colombo area having one or more of above features have been

selected for the analysis.

According to the concise Oxford English dictionary (Indian Edition), 2007, office building is a building

used as place of business for clerical, administrative, or similar work.

19

Following office buildings have been identified for the analysis.

1. Project Office of Greater Colombo Urban Transport Development Project (OCH) Southern

Section from Kaduwela to Kottawa, Road Development Authority, Udumulla Road, Battaramulla

No. of floors – 01

Floor area – 550 m2

2. Wing 4G of Bandaranayake Memorial International Conference Hall (BMICH), Bauddhaloka

Mawatha, Colombo 07



3. Air Mech (Pvt) Ltd, No. 73 B, Nugegoda Road, Papiliyana, Boralasgamuwa.



4. Sri Lanka Standard Institute (SLSI), No. 17, Victoria Place, Alwitigala Mawatha, Colombo 08.



5. World Trade Center (WTC), No. 18-01, Colombo 01



The buildings were selected based on the number of floors to cover both possible scenarios of low rise

and high rise buildings.

3.2 Collection of data for calculation of the building envelop

properties

Following measurements were obtained for each building mentioned in section 3.1 for the calculation of

the OTTV of the existing building. These parameters were identified as specified in the building code.

1. Plan view, front elevation and side elevation drawings of the building

2. Building construction material and thickness of each layer of the building envelop

3. Types and height of shading devices

4. Building orientation

3.3 Modeling of indoor climate

The DesignBuilder software was used for the indoor climate modeling. Following assumptions in table 3.1

were made for the modeling purposes in order to maintain the similar indoor activities and conditions for

all buildings.

20

Parameter Value Units

Occupancy Density (People/100m2) 7

Metabolic rate Light office work /standing

/walking

123 W/human

Factor (1-Men, 0.85-

women,0.75-children)

0.9

Clothing Summer 0.6 Clo

Cooling Set point temperature 24 0C

Fresh air Ventilation, rate 10 (l/s. person)

Lighting Illuminance 500 Lux

Lighting density 10 W/m2

Infiltration 2 l/s.m2

Heat Dissipation No. of Computers / 100m2 4

Heat dissipation from

computers

3 W/m2

Office equipment 3 W/m2

Miscellaneous 3 W/m2

HVAC System Template Fan coil

Sizing Method ASHRAE heat balance

Site Location Latitude 6.49 0

Longitude 79.52 0

Site details Elevation above sea level 5 m

Monthly temperature January 26.6 0C

February 26.1 0C

March 27.7 0C

April 28.3 0C

May 28.8 0C

June 27.8 0C

July 27.3 0C

August 27.1 0C

September 27.6 0C

October 27.1 0C

November 26.4 0C

December 26.2 0C

Time Zone (GMT+06.00) Sri

Jayawardhanapura

Simulation Weather data LKA_COLOMBO_RATHMALANA_

SWERA

Table 3-1: Assumptions and data used for buildings simulation

Following steps were followed to identify the correlation between the OTTV, and annual cooling energy

of a building.

1. 1st Step - Calculate existing OTTV manually and find the respective annual cooling energy

using DesignBuilder simulation.

21

The OTTV of the building was calculated considering the existing building properties

such as construction materials, orientation, window to wall ratio, shading coefficients etc.

Properties of the construction materials were extracted from the DesignBuilder software.

Then annual cooling energy was found using DesignBuilder.

2. 2nd Step - Reduce the OTTV by introducing different construction materials for walls, windows

and roof with low thermal transfer values and find the respective annual cooling energy using

DesignBuilder simulation.

Followings are the modifications carried out individually for the existing buildings,

i. Introduce double layer glazing for the windows

ii. Introduce insulations for the walls

iii. Introduce insulations for the roof

iv. Introduce insulations to walls and roof in order to obtain the maximum U values

prescribed for facades and roofs in warm humid, day time operation buildings in the

building code

Further to above common modifications, some more modifications have been done specific to each

building depending on the existing building envelope parameters.

3.3.1 Building 1: Project Office of Greater Colombo Urban Transport

Development Project

This is a single story office building with a floor area of 550 m2. Length, width and height of the building

is 38 m, 12m and 3m respectively. Building is oriented in north-south direction. Walls of the building are

made from masonry block and 3mm thick single clear glasses are used for windows. Galvanized steel

sheets are used for the roof.

3.3.1.1. Layout diagram of the existing building 1

Below diagram shows the existing layout diagram modeled in the software using the measurements

obtained from the actual building.

22

Figure 3-1: Layout diagram of the existing building 1 (Extracted from DesignBuilder)

3.3.1.2. Summary of the results of building 1

U values of the construction materials of walls, window and roof are 3.098 W/m2.K, 6.257 W/m2.K and

7.141 W/m2.K respectively. According to the prescriptive requirements of the building code, the

maximum U values for the wall and roofs of an office building located in Colombo area are 0.45 W/m2.K

and 0.3 W/m2.K respectively. Therefore this building is not met the prescriptive requirements of the

Code. OTTV of the existing building is 47 W/m2. Calculated OTTV of the building for prescriptive

requirements is 12.3 W/m2. In order to comply the building with the code the OTTV should be lesser

than 50 W/m2 as well as 12.3 W/m2. Therefore this building is not complying with the code.

More details on thermal properties and lay out diagrams of the construction materials and OTTV

calculations are provided in section 1 of annex 1.

Following table shows the absolute and percentage change of OTTV and annual cooling energy with

modifications.

23

Modification

Overall Thermal Transfer

Value (OTTV),

W/m2

Annual cooling energy, MWh

Specific energy

consumption, MWh/m2

Percentage reduction of OTTV,

%

Percentage reduction of

annual cooling energy,

%

Existing building 47.1 87.5 0.159 N/A N/A

Introduce double layer glazing 46.5 87.7 0.159 1.27 (0.23)

Introduce insulation to walls 43.8 84.4 0.153 7.01 3.54

Introduce insulation to roof 46.7 87.5 0.159 0.85 0.00

Introduce insulations to walls

and roof, in order to achieve

the maximum U values for

facades and roofs specified in

Building Code

12.3 84.4 0.153 73.89 3.54

Reduce WWR 46.4 87.3 0.159 1.46 0.25

Reduce WWR and Introduce 1m Overhangs to windows

41.9 84.7 0.154 11.08 3.18

Reduce WWR , Introduce 1m Overhangs to windows and change the wall materials to brick

41.4 83.2 0.151 12.17 4.89

Reduce WWR , Introduce 1.5 m Overhangs to windows and change the wall materials to brick

41.3 82.7 0.150 12.39 5.45

Reduce WWR , Introduce 1.5 m Overhangs to windows and change the wall and roof materials to brick and clay tiles respectively

36.5 83.2 0.151 22.46 4.97

Table 3-2: Absolute and percentage reduction of OTTV and annual cooling energy with

modifications of building 1

Introduction of double layer glazing has resulted a reduction of OTTV but it has increased the annual cooling energy. Introduction of insulation to roof has no impact on cooling energy. All other modifications have resulted in reduction of both OTTV and annual cooling energy.

Following graph shows the variation of annual cooling energy with the OTTV.

24

Figure 3-2: Variation of the annual cooling energy with the OTTV of the building 1

The data points can be approximately represented by a second order polynomial with R2 value of 0.861.

It can be observed that up to a certain point the cooling energy reduces with the reduction of OTTV. But

afterward the cooling energy increases while the OTTV decrease.

3.3.2 Building 2: Wing 4 G of Bandaranayke Memorial International

Conference Hall

Bandaranayke Memorial International Conference Hall (BMICH) is a building complex with many office

compartments. Only wing 4 G has been considered for this study. It is a three storey building having

approximate area of 1600m2. The building is oriented in North-West and South-East direction. Two sides

of the building have shaded due to the adjacent buildings. Walls of the building are made from 225mm

thick burned brick and 3mm thick single clear glasses are used for widows. A concrete slab is used as the

roof.



obtained from the actual building. It has been used component blocks in order to incorporate the shading

effect of the surrounding buildings. There are shading effect due to the verandahs in exterior walls in long

axis also. The components blocks in blue and magenta color shows in Figures 3.2 are used to incorporate

the shading effects due to adjacent buildings and external verandah respectively.

Length of the building = 47 m

Width of the building = 11 m

Slab to Slab height = 3.7 m

25

Figure 3-3: Layout diagram of the existing building 2

(Extracted from DesignBuilder)








than 19.1 W/m2. Therefore this building is not complying with the code. More details on thermal

properties, and lay out diagrams of the construction materials and calculations are provided in section 2 of

annex 1.

Following table shows the absolute and percentage change of OTTV with annual cooling energy with

modifications.

26

Modification


Value (OTTV),

W/m2


Specific energy consumption,

MWh/m2

Percentage reduction of OTTV, %


annual cooling

energy, %


Introduce double layer glazing

23.0 446.72 0.279 8.37 -4.32

Introduce insulation to walls

23.4 409.34 0.256 6.77 4.41

Introduce insulation to roof

22.8 419.41 0.262 9.16 2.06

Introduce insulations to walls and roof, in order to achieve the maximum U values for facades and roofs specified in Building Code

19.1 427.99 0.267 23.9 0.05

Reduce WWR 22.7 442.55 0.277 9.56 -3.35

Reduce WWR, introduce double layer glazing for windows and introduce insulations to wall

19.1 410.59 0.257 23.75 4.12

Table 3-3: Absolute and percentage reduction of OTTV and annual cooling energy with modifications of building 2

Introduction of double layer glazing and reduction of WWR has resulted a reduction of OTTV but it has

increased the annual cooling energy. All other modifications have resulted in a reduction of annual cooling

energy requirement.


27


A relationship could not be found between the data points. In some cases, totally different annual cooling

energies for approximately same OTTV can be observed.

3.3.3 Building 3: Air- Mech Engineering Office

Air- Mech is a 4 storey office building having approximate floor area 500m2. The building is oriented in

North-South direction. Walls of the building are made from 225mm thick burned brick and 3mm thick

single clear glasses are used for widows. A concrete slab is used as a roof.

Length of the building = 15 m

Width of the building = 10 m

Height of ground floor = 3.5 m

Slab to Slab height of 1st, 2nd and 3rd floors = 3 m




405

410

415

420

425

430

435

440

445

450

15 17 19 21 23 25 27

BMICH

BMICH


OTTV, W/m2

28







and 0.4 W/m2.K respectively. Therefore this building has not met the prescriptive requirements of the



than 47.4 W/m2. Therefore this building is not complying with the code.

More details on thermal properties, and lay out diagrams of the construction materials and calculations are

provided in section 3 of annex 1.

Following table shows the absolute and percentage change of OTTV and annual cooling energy with

modifications.

29

Modification


Value (OTTV),

W/m2



MWh/m2



annual cooling

energy, %



52.8 156.25 0.313 4.52 0.43


51.3 158.02 0.316 7.31 -0.69


46.9 149.87 0.300 15.19 4.50


47.4 153.80 0.308 14.29 1.99

Introduce insulation to walls and roof

49.8 142.96 0.286 9.98 8.90

Introduce insulation to walls and roof and reduce WWR

44.0 138.75 0.278 20.47 11.58

Introduce insulation to walls and roof , reduce WWR and introduce 1m Overhangs to windows

29.5 124.04 0.248 46.69 20.96


Introduction of insulations to wall has resulted a reduction of OTTV but it has increased the annual

cooling energy by 0.7%. All other modifications have resulted in a reduction of both OTTV and annual

cooling energy requirement.


30


The data points can be represented by a linear graph with R2 value of 0.838.

3.3.4 Building 4: Sri Lanka Standards Institute (SLSI)

SLSI is an 8 storey office building having approximate floor area of 6100m2. Walls of the building are

made from 225mm thick burned brick and 3mm thick single clear glasses are used for widows. A concrete

slab is used as a roof. The building is shaded by the buildings and trees in all directions except south.

Building has an open court yard at the middle. This building is surrounded by shady trees and some

buildings from three sides. This factor also has been considered when calculating the OTTV values and

simulations.



obtained from the actual building. The components blocks in blue and magenta color shows in Figures

3.4 are used to incorporate the shading effects due to adjacent buildings and external verandah

respectively.

31



3.3.4.2. Summary of the results of building 4.






requirements is 32 W/m2. In order to comply the building with the code the OTTV should be lesser than

32 W/m2. Therefore this building is not complying with the code.

More details on thermal properties, and lay out diagrams of the construction materials and calculations are

provided in section 4 of annex 1.

Following table shows the absolute and percentage change of OTTV with annual cooling energy with

modifications.

32

Modification


Value (OTTV),

W/m2



MWh/m2



annual cooling

energy, %

Existing building 44.2 1,650 0.270 N/A N/A


41.0 1,660 0.272 7.24 -0.61


39.6 1,510 0.248 10.41 8.48


38.7 1,610 0.264 12.44 2.42


32.0 1,662 0.272 27.60 -0.73

Reduce WWR 39.7 1,630 0.267 10.18 1.21

Reduce WWR and Introduce insulation to walls

34.6 1,500 0.246 21.72 9.09


Introduction of double layer glazing has resulted an increase of the annual cooling energy by 0.6%.

Introduction of insulations to walls and roof, as specified in Building Code also has resulted an increase of

the annual cooling energy by 0.73%. All other modifications have resulted a reduction of the annual

cooling energy.


33


A clear relationship could not be found between the data points. This could have been due to extreme

data points. Therefore a further analysis was carried out by eliminating extreme data points. When the

data points (39.6, 1510) and (32.0, 1662) were removed, following graph could be obtained.

Figure 3-9: Variation of the annual cooling energy with the OTTV of the building 4 (after

removing two data points)

Above data set displays a linear relationship with R2 of 0.799.

1,480

1,500

1,520

1,540

1,560

1,580

1,600

1,620

1,640

1,660

1,680

30 35 40 45 50 55 60

SLSI

SLSI


OTTV, W/m2

y = 16.47x + 957.0R² = 0.799

1,450

1,500

1,550

1,600

1,650

1,700

30 35 40 45

SLSI

SLSI

Linear (SLSI)


OTTV, W/m2

34

3.3.5 Building 5: World Trade Centre (WTC)

WTC is high rise building having 37 storeys. It has twin towers. There are several offices building in this

space and floor area is around 81,500m2. The building is shaded by the buildings located in east and west

directions. Unconditioned car park is attached to the Southside wall of the ground floor. Therefore it is

assumed that there is no solar heat gains through that wall and do not consider it for OTTV calculation.






3.3.5.2. Summary of the results of building 5.

U values of the construction materials of walls, window and roof are 2.37W/m2.K, 6.121 W/m2.K and




Code. OTTV of the existing building is 87.6 W/m2. Calculated OTTV of the building for prescriptive

requirements is 84.4 W/m2. In order to comply the building with the code the OTTV should be lesser 50

W/m2. Therefore this building is not complying with the code. More details on thermal properties, and lay

out diagrams of the construction materials and calculations are provided in section 5 of annex 1.

In order to reduce the OTTV, following parameters were changed. Following table shows the absolute

and percentage change of OTTV with annual cooling energy for modifications done.

35

Modification


Value (OTTV),

W/m2



MWh/m2



annual cooling

energy, %

Existing building 87.8 33,200 0.407 N/A N/A


81.8 33,091 0.406 6.1 0.3


84.8 32,962 0.404 2.9 0.7


85.1 33,175 0.407 1.1 0.1


82.8 33,107 0.406 3.7 0.3

Table 3-6: Absolute and percentage reduction of OTTV and annual cooling energy with modification of building 5

In this building all the modifications have resulted reduction of both OTTV and annual cooling energy.



36

A clear relationship could not be found between the data points. This could have been due to extreme

data points. Therefore, a further analysis was carried out by eliminating extreme data points. When the

data points (84.8, 32962) were removed, following graph could be obtained.

Figure 3-12: Variation of the annual cooling energy with the OTTV of the building 5(after

removing two data points)

Above data set displays a linear relationship with R2 of 0.946.

y = 19.06x + 31534R² = 0.946

32,800

32,850

32,900

32,950

33,000

33,050

33,100

33,150

33,200

33,250

81.0 82.0 83.0 84.0 85.0 86.0 87.0 88.0 89.0

WTCAnnual cooling energy, MWh

OTTV, W/m2

37

4 Analysis of Results

This chapter provides a detailed analysis of the simulation results. There are 3 sections namely; analysis of

simulation results, cost benefit analysis for enhanced energy efficiency building and identification of the

optimum building models. In the cost benefit analysis the LCC was calculated using the incremental cost

of modifications to the existing building. Finally optimum building envelop models were identified based

on the cost benefit analysis.

4.1 Analysis of Simulation Results

The main objective of specifying the maximum U values and OTTV for the building envelop is to reduce

the cooling energy requirement of the building. A proportional relationship between the OTTV and the

annual cooling energy was expected. But in some cases this has not happened. Table 4.1 and Table 4.2

summarize the situations where unexpected increase of annual cooling energy with the reduction of

OTTV and observed relationship between OTTV and annual cooling energy respectively.

Building Modifications resulted in an increase of annual cooling energy

requirement with compared to existing building

Building 1 (RDA) Introduction of double layer glazing

Building 2 (BMICH) 1. Introduce insulations to walls

2. Reduction of WWR

Building 3 (Air Mech) Introduction of insulations to walls

Building 4 (SLSI) 1. Introduction of double layer glazing

2. Introduce insulations to walls and roof, in order to achieve the

maximum U values for facades and roofs specified in Building

Code

Table 4-1: Building modifications resulted to increase of annual cooling energy

It can be observed that even for the same modification, there are different behaviors in different

buildings. Which means that the required envelop properties to optimize cooling energy requirement of a

building is unique for each building.

Building Relationship between OTTV

and annual cooling energy

R2 Value

Building 1 (RDA) Second order polynomial 0.836

Building 2 (BMICH) None N/A

Building 3 (Air Mech) Linear 0.838

Building 4 (SLSI) None N/A

Building 5 (WTC) None N/A

Table 4-2: Relationship between OTTV and annual cooling energy

As per above table, only building 1(RDA) and building 3 (Airmech) shows a positive relationship between

the OTTV and cooling energy requirement. Any of the other buildings do not show any relationship.

Therefore further analysis is required to assess the other factors which have not been considered for

above analysis.

38

4.2 Cost benefit analysis for enhanced energy efficiency

building envelops applications

Ultimate objective of the Energy Efficient Building Code is to optimize the energy usage and related

energy cost. A cost benefit analysis was carried out to assess the optimum building envelop model.

Average incremental cost was calculated using market rates for each modification done. This cost is

compared against the long term cost saving due to reduction of annual cooling energy. Life Cycle Cost

was calculated for each option by assuming electricity tariff of LKR.20 and percentage cost of capital 12%

to be constant for 20 year period. The option with the minimum Life Cycle Cost (LCC) is considered as

the preferred option.

Tables 4.3 to 4.7 summarize the Life Cycle Cost calculation for each building element change. Preference

is given for the option with lesser Life Cycle Cost.

39

4.2.1 Building 1 (RDA)

Modification

OTTV, W/m2


Incremental Cost, LKR

Annual cost for

energy, LKR

Million

Present value of 20 year energy cost, LKR

Million

Total Life

Cycle cost, LKR

Million

Preference

Existing building 47.1 87.5 N/A 0.963 7.19 7.19 6


46.5 87.7 103,400 0.965 7.21 7.31 8


43.8 84.4 834,328 0.928 6.93 7.77 9


46.7 87.5 85,006 0.963 7.19 7.27 7

Introduce insulations to walls and roof, in order to achieve the maximum U values for facades and roofs specified in Code

12.3 84.4 1,274,146 0.928 6.93 8.21 10

Reduce WWR 46.4 87.3 -73 0.960 7.17 7.17 5

Reduce WWR and Introduce 1m Overhangs to windows

41.9 84.7 88,117 0.932 6.96 7.05 1

Reduce WWR , Introduce 1m Overhangs to windows and change the wall materials to brick

41.4 83.2 231,341 0.915 6.84 7.07 3

Reduce WWR , Introduce 1.5 m Overhangs to windows and change the wall materials to brick

41.3 82.7 274,412 0.910 6.80 7.07 4

Reduce WWR , Introduce 1.5 m Overhangs to windows and change the wall and roof materials to brick and clay tiles respectively

36.5 83.2 231,269 0.915 6.83 7.06 2

Table 4-3: LCC for different modifications of building 1

Based on the minimum LCC, Reduce WWR and introduce 1m overhangs to windows can be considered

as the preferred option for the building 1 from the options considered.

40

4.2.2 Building 2 (BMICH)

Modification OTTV, W/m2



Annual cost for

energy, LKR

Million


Million

Total Life

Cycle cost, LKR

Million

Preference



23.0 446.72 833,250 4.91 36.70 37.54 6


23.4 409.34 1,989,010 4.50 33.63 35.62 2


22.8 419.41 2,720,490 4.61 34.46 37.18 5


19.1 427.99 3,539,181 4.71 35.16 38.70 7

Reduce WWR 22.7 442.55 -9,293 4.87 36.36 36.35 3

Reduce WWR and Introduce double layer glazing and introduce insulations to wall

19.1 410.59 2,778,900 4.52 33.73 36.51 4


Based on the minimum LCC, the existing building envelop is the preferred option for the building 2 from

the options considered.

41

4.2.3 Building 3 (Air-Mech)




Annual cost for

energy, LKR

Million


Million

Total Life

Cycle cost, LKR

Million

Preference



52.8 151.1 448,800 1.66 12.41 12.86 2


52.7 152.2 1,395,183 1.67 12.50 13.90 6


52.5 151.1 592,137 1.66 12.41 13.01 3


47.4 153.8 1,684,045 1.69 12.64 14.32 7

Introduce insulation to walls and roof

49.78 142.96 1,987,320 1.57 11.75 13.73 5

Introduce insulation to walls and roof and reduce WWR

43.98 138.75 2,027,607 1.53 11.40 13.43 4

Introduce insulation to walls and roof , reduce WWR and introduce 1m overhangs to windows

29.48 124.04 4,901,422 1.36 10.19 15.09 8




42

4.2.4 Building 4 (SLSI)




Annual cost for

energy, LKR

Million


Million

Total Life Cycle cost,

LKR Million

Preference

Existing building

44.2 1,650 N/A 18.15 135.56 135.56 3


41.0 1,660 3,707,000 18.26 136.38 140.09 6


39.6 1,510 6,380,036 16.61 124.06 130.44 1


38.7 1,610 3,886,848 17.71 132.28 136.16 4


32.0 1,662 8,416,310 18.28 136.55 144.96 7

Reduce WWR 39.7 1,630 -52,346 17.93 133.92 133.92 2

Reduce WWR and Introduce insulation to walls

34.6 1,500 14,706,064 16.50 123.24 137.94 5


Based on the minimum LCC, Introduce insulation to walls is the preferred option for the building 4 from the options considered.

43

4.2.5 Building 5 (WTC)




Annual cost for energy,

LKR Million


Million

Total Life Cycle cost,

LKR Million

Preference

Existing building

87.8 33,200 N/A 365.20 2,727.68 2,727.68 1


81.8 33,091 20,123,707 364.00 2,718.72 2,738.85 3


84.8 32,962 34,105,423 362.58 2,708.12 2,742.23 4


85.1 33,175 10,587,612 364.93 2,725.62 2,736.21 2

As per maximum U values for facades and roofs specified in Building Code

82.8 33,107 38,423,984 364.18 2,720.04 2,758.46 5




4.3 Summary of the optimum building envelops models

Building envelops can be designed to optimize the energy performance based on the above LCC

calculation. As per the cost benefit analysis, following building envelop changes can be recommended as

most energy effective methods from the options considered, for the buildings considered.

Building Preferred Method

RDA Reduce WWR and Introduce 1m Overhangs to windows

BMICH Existing building

Air-Mech Existing building

SLSI Introduce insulation to walls

WTC Existing building

Table 4-8: Recommended modification for buildings

44

Existing buildings envelops of BMICH, Air-Mech and WTC can be recommended as the optimum

solution based on the LCC method. Reduction of WWR and introduction of 1m overhangs to windows

can be considered as the most preferred option for RDA while introduce insulation to walls can be

considered as the most preferred option for SLSI.

45

5 Discussion and Conclusion

This chapter discusses the outcomes of the study, sensitivity of the measurement, recommendations to

improvements of code of practice for energy efficient buildings.

During the study, different relationships between OTTV and cooling energy requirement of buildings

were observed. A second order polynomial distribution with R2 of 0.861 and a linear distribution with R2

of 0.838 were observed for a single storey RDA building and 3 stories Airmech building respectively.

However any specific relationship was not identified for BMICH, SLSI and WTC buildings which have 3,

8 and 37 stories respectively.

Following table shows the specific annual cooling energy requirement variation with the OTTV of the

buildings considered.

RDA BMICH Air mech SLSI WTC

OTTV, W/m2

Specific annual cooling energy,

MWh/m2

OTTV, W/m2


MWh/m2

OTTV, W/m2


MWh/m2

OTTV, W/m2


MWh/m2

OTTV, W/m2


MWh/m2

47.1 0.159 25.1 0.268 55.3 0.314 44.2 0.270 87.8 0.407

46.7 0.159 23.4 0.256 52.8 0.313 41.0 0.272 85.1 0.407

46.5 0.159 23.0 0.279 51.3 0.316 39.7 0.267 84.8 0.404

46.4 0.159 22.8 0.262 49.8 0.286 39.6 0.248 82.8 0.406

43.8 0.153 22.7 0.277 47.4 0.308 38.7 0.264 81.8 0.406

41.9 0.154 19.1 0.257 46.9 0.300 34.6 0.246 - -

41.4 0.151 19.1 0.267 44.0 0.278 32.0 0.272 - -

41.3 0.150 - - 29.5 0.248 - - - -

36.5 0.151 - - - - - - - -

12.3 0.153 - - - - - - - -

Table 5-1: Variation of OTTV and specific annual cooling energy requirement with modification for buildings

Following graph shows the specific annual cooling energy requirement variation with the OTTV of the

buildings considered.

46

Figure 5-1: Variation of specific annual energy consumption Vs OTTV for buildings

As shown in above graph, it is not possible to predict a common relationship between OTTV and specific

annual cooling energy requirement for all the buildings considered. The annual cooling energy has

increased in following instances, even though the OTTV has reduced.

1. Introduction of double layer glazing (RDA/SLSI)

2. Introduction of insulations to walls (BMICH / Airmech)

3. Reduction of WWR (BMICH)

4. Introduction of insulations to both walls and roof (SLSI)

Air-Conditioning energy requirement of a building depend on both external and internal heat gains.

External gains include solar heat gain through windows, walls, doors and roof, heat gains through

infiltration and ventilation. Internal gains include heat release by occupants in the space, lighting systems,

equipments etc. The thermal mass of the building also affect to the cooling energy. Therefore in order to

reduce cooling energy it is required to reduce all these heat gains. By introducing insulations to the

building envelop and proper shadings, the solar heat gains can be minimized. OTTV accounts major three

heat gains namely; Heat conduction through opaque section of wall and roof, Heat conduction through

fenestration and Solar heat gain through fenestration. Therefore the reduction of external heat gains via

increasing the insulations cause reduction of OTTV.

In case where the external temperature is lower than the internal temperature (ex: during night

hours/rainy days) there will be a heat outflow which will effectively reduce the cooling energy. When the

insulation is increased, this heat outflow also will be minimized and will result in increased cooling energy

requirement. This phenomenon is the reason for the increased cooling energy requirement even when the

OTTV is reduced in above instances.

47

The accuracy of the results depends on accuracy of assumptions made, weather details, thermal properties

of building construction materials and simulation software. Following are some potential reasons

identified for any deviation from the actual results.

1. In order to maintain the similar indoor conditions for all buildings, it was assumed the same

parameters for all buildings such as occupancy density, occupancy pattern, metabolic rate,

clothing, cooling set point temperature, fresh air requirement, luminance level, lighting density,

infiltration, heat dissipation, elevation as mentioned in table 3.1. The annual cooling energy was

calculated based on these values. But the actual situation of the building might have been

different. The actual occupancy density and patterns, clothing levels, lighting requirement etc

might vary from one building to another. Therefore the actual cooling energy requirement may

not equal to the simulated value. Any error in these assumptions might have caused errors in

annual energy calculation.

2. In order to incorporate the shading effect of the buildings and vegetations, and the effect of

attached unconditioned spaces such as warehouses, car parks component blocks were used in

simulation. There may be slight difference between the simulated results and the actual results.

3. The thermal properties of construction materials were obtained from the “DesignBuilder”

software since the exact values of the materials used in Sri Lanka are not available. If the

properties of the actual materials are different, there can be errors in the OTTV as well as annual

cooling energy.

4. The simulation was carried out using the “DesignBuilder” software. The simulation software

may not be able to simulate precisely the equipment behaviors, building shapes and conditions

that exist in the building. If there is any modeling/software error, this might cause errors in the

annual cooling energy.

The impact on cooling energy requirement from envelop parameter modification is unique for each

building. In some instances the reduction of OTTV has not resulted in any reduction of the cooling

energy requirement. There is a combined effect from each building component which affects the final

energy requirement. A simulation based technique is recommended to be used to find the optimum

building envelop design to minimize the annual cooling energy requirement. And also it is recommended

to carry out a cost benefit analysis for the possible designs in order to find the most cost effective design.

This study was carried out only for 5 commercial buildings representing low rise to high rise located in a

warm humid climate. These buildings had drastically different envelop parameters. In this study OTTV

reductions of buildings were achieved by introducing insulations to the envelop elements, changing WWR,

introducing external shadings of the building for OTTV reductions. The accuracy of the derivations can

be increased by observing a fairly large number of buildings incorporating more modifications using the

software.

Within the limited time period, this study was carried out to find the behavior of annual cooling energy

requirement with the reduction of OTTV. The OTTV of the existing building was considered as the

maximum value. Further studies need to be carried out to identify the variation of energy performance

with the increase of OTTV.

48

The thermal properties of the construction materials were obtained from the DesignBuilder software for

the OTTV calculation. The exact properties of the building material used in Sri Lanka were not available.

A proper research need to be carried out to identify the material properties precisely.

Based on the results, following improvements can be suggested for further improvements of the building

code.

1. Any of the building considered did not comply with the prescriptive values of the code. U values

of the wall and roof materials were above the maximum value specified. Cumulative OTTV of all

buildings were above the corresponding OTTV estimated using prescriptive values. And also

there are huge incremental costs involved to achieve these requirements. But the benefit is much

lower or negligible. OTTV of the RDA, BMICH, Air-Mech, SLSI and WTC buildings were 47.1

W/m2, 25.1 W/m2, 55.3 W/m2, 44.2 W/m2 and 87.8 W/m2 respectively. Only 3 buildings RDA,

BMICH and SLSI were under the threshold value of 50 W/m2. It is recommended to revise these

maximum values in reviews.

2. Standard U value tables of the construction materials are not available in the present code. It is

suggested to include these tables, and then the building designers can select appropriate materials

and thickness.

3. A detailed guide line to be provided as a supplement to the existing building code, providing

following information.

a). Passive building technologies such as roof top gardens, Wet walls, ponds, natural ventilation

and lighting. Details shall be provided as applicable for different climate zones.

b). Calculation methodology of OTTV considering building attachments (garage, Verandah,

corridor) to the main building.

4. Only the shading effects from projections are considered for the OTTV calculations. The

shadings provided by the vegetations, nearby buildings are not captured in the current OTTV

formula. If these can be captured, the values denoted by OTTV will be more accurate.

5. A simulation based analysis to be recommended in the building code in order to assess the

optimum building envelope parameters.

49

6 Bibliography

1. U. S. Energy Information Administration, 2010, International Energy Outlook 2010, Office of

Integrated analysis and forcasting, U.S. Department of Energy, Washington, Available online at

http://www.eia.gov/oiaf/ieo/index.html

2. Sri Lanka Sustainable Energy Authority, 2007, Sri Lanka Energy Balance 2007, Sri Lanka

Sustainable Energy Authority, Colombo, Sri Lanka.

3. Jens Laustesen,2008, Energy Efficiency requirements in building codes, energy efficiency policies for new

buildings, International Energy Agency,Paris Cedex 15, France.

4. Sri Lanka Sustainable Energy Authority, 2009. Code of practice for energy efficient buildings in Sri

Lanka – 2008. : Sri Lanka Sustainable Energy Authority, Colombo, Sri Lanka.

5. American Society of Heating, Refrigerating and Air-Conditioning Engineers, 2004,

ANSI/ASHRAE/IESNA Standard 90.1-2004 “Energy Standard for Buildings Except Low-Rise

Residential Buildings”, American Society of Heating, Refrigerating and Air-Conditioning Engineers,

Inc., Atalanta, America

6. Bureau of Energy Efficiency,2009,Energy Conservation Building Code User Guide, Bureau of Energy

Efficiency, New Delhi, India, ISBN 978-81-909025-3-3.

7. Faye C. McQuiston, Jerald D. Parker and Jeffrey D. Spitler, 2005,Heating, Ventilating, and Air

Conditioning Analysis and Design,Sixth edition, John Wiley & Sons, Inc., United States of America,

ISBN 978-0-471-47015-1.

8. Sri Lanka Climate profile, http://www.climatechange.lk/Climate_Profile.html

9. Efficient windows collabaratives, Available online at http://www.efficientwindows.org/vt.cfm

10. F.W.H Yik and K.S.Y Wan, 2005, An evaluation of the appropriateness of using overall thermal transfer

value (OTTV) to regulate envelope energy performance of air-conditioned buildings, Elesvier, Available online

at www.sciencedirect.com

11. Mansour Nikpour, Mohd Zin kandar, Mohammad Ghomeshi, Nima Moeinzadeh and

Mohsen Ghasemi, 2011, Self Shaded strategy in high-rise buildings effect on minimizing the amount of

OTTV, International Journal of Civil and Environmental Engineering 3:2 2011, 111-116, available

online at http://www.waset.org/journals/ijcee/v3/v3-2-18.pdf

12. Sam C M Hui and Joseph C Lam, 1991, Overall Thermal Transfer Value (OTTV) – a review, Hong

Kong Engineer / September 1991, 26 – 32, available online at www.arch.hku.hk/~cmhui/ottv-

review.pdf

13. Catherine Soanes and Angus Stevenson, 2007, Concise Oxford English dictionary (Indian Edition),

Oxford university Press, New Delhi, India

http://www.eia.gov/oiaf/ieo/index.html

http://www.climatechange.lk/Climate_Profile.html

http://www.sciencedirect.com/

http://www.waset.org/journals/ijcee/v3/v3-2-18.pdf

http://www.arch.hku.hk/~cmhui/ottv-review.pdf

http://www.arch.hku.hk/~cmhui/ottv-review.pdf

50

14. W.R. Chan, P.N. Price, A.J. Gadgil, Sheltering in Buildings from Large-Scale Outdoor Releases, Air

Infiltration and Ventilation Centre Ventilation Information Paper, LBNL-55575

15. Faye C.McQuiston, Jerald D.Parker and Jeffrey D. Spitler, 2005, Heating, Ventilating, and air

Conditioning analysis and design, John Wiley & Sons, Inc., America.

16. Ministry of Non Conventional Energy Sources, 2002, Energy Efficient building in India, Tata

Energy Recourse Institute, India.

17. Public Utilities commission of Sri Lanka, 2011, Electricity tariff 2011, available on line at

http://www.pucsl.gov.lk/download/Electricity/Tariffs%20Extention-English-2011.pdf, accessed

on

http://www.pucsl.gov.lk/download/Electricity/Tariffs%20Extention-English-2011.pdf

51

ANNEXURE 1: Calculation of OTTV and annual cooling

energy of buildings

1. Building 1: Project Office of Greater Colombo Urban

Transport Development Project (OCH) Southern Section from

Kaduwela to Kottawa, Road Development Authority (RDA),

Udumulla Road, Battaramulla

1.1. OTTV and annual cooling energy for existing building

1.1.1 U values of elements of the existing building

U values for each building component were calculated using the properties of the existing buildings’

construction material for each element. Following table shows the conductivity, specific heat, density and

thickness of the each layer of the wall construction and U value of the wall.

Wall materials Conductivity,

W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Gypsum plastering 0.8 840 1300 2

Cement plaster, Sand aggregate 0.72 840 1860 10

Masonry block 0.85 840 1650 102



Uw , W/m2.K 3.098

Table 01: Properties of construction materials and U value of the wall of existing building 1

(Adapted from DesignBuilder)

Following Figure shows a cross section of a wall of existing building.

Figure 01: Cross section of the wall of existing building 1 (Adapted from DesignBuilder)

52

Single layer, 3mm thick glass are used for the windows and following table shows the conductivity and U

value of the glass.

Material Conductivity, W/m.K Thickness, mm

Single clear glass 0.9 3

Uf, W/m2.K 6.257

Table 02: Properties and U value of existing window construction materials of the building 1


The roofing material and properties are shown in below;

Material Conductivity,

W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Galvanized steel sheet 50 450 7800 2

U, W/m2.K 7.141

Table 03: Properties and U value of roof construction materials of the existing building 1 (Adapted

from DesignBuilder)

The floor construction material and properties are shown in below;

Conductivity,

W/m.K

Specific Heat,

J/kg.K Density, kg/m3 Thickness, mm

Floor/ Roof Screed 0.41 840 1200 70

Cast Concrete 1.13 1000 2000 100

U, W/m2.K 7.141

Table 04: Properties and U value of floor construction materials of the existing building 1 (Adapted

from DesignBuilder)

Following Figure shows a cross section of a floor of existing building.

Figure 02: Cross section of the floor of building 1 (Adapted from DesignBuilder)

53

1.1.2. Calculation of Window to Wall Ratio (WWR)

Following Figure shows the layout diagram of the building. It has numbered the wall faces as indicate in

the Figure for OTTV calculation. WWR of faces were calculated based on measured data.

Figure 03: Layout diagram of building 1 (Adapted from DesignBuilder)

There are no windows in wall 1 and 3.

WWR of face 2

Window area

= (1.95*1.2*8) + (2*0.5*0.5)

= 19.22 m2

Wall area

= 38 * 3

= 114 m2

WWR

= 0.17

WWR of face 4

Window area

= (6*1.95*1.2) + (3*1.2*1.2)

= 18.36 m2

Wall area

= 38 * 3

= 114 m2

WWR

= 0.16

1.1.3. Calculation of Shading Coefficient of windows

There are no external shadings in the existing building.

N

54

1.1.4. Calculation of OTTV

The OTTV for the existing building was calculated using above U values. Below table shows the

calculation of OTTVs for each building component and overall building.

Wall Face/Roof Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

1 36 19.3 0.3 0.00 3.098 3.6 6.257 186 1 0.95 18 646

2 114 19.3 0.3 0.17 3.098 3.6 6.257 186 1 0.9 47 5378

3 36 19.3 0.3 0.00 3.098 3.6 6.257 186 1 0.79 18 646

4 114 19.3 0.3 0.16 3.098 3.6 6.257 186 1 1.34 59 6675

Roof 549 7.9 0.86 0.00 7.141

49 26647

OTTV 47

Table 05: OTTV of the existing building 1

1.1.5. Annual Cooling energy

By simulating the building with above parameters in the DesignBuilder software the annual cooling energy

of the building was found.

Annual cooling energy = 87.5 MWh

1.2. OTTV and annual cooling energy for modified building:

Introduce double layer glazing for windows

1.2.1 U values of the window glazing

Double layer, 3mm thick glasses and air layer are used for the windows and following table shows the

conductivity and U value of the glass.


Single Clear Glass 0.9 3

Air - 13


Uf, W/m2.K 2.761

Table 06: Properties and U value of double layer window construction materials of the building 1



Following table shows the OTTV of the modified building.

55

Wall

Face/Roof Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

1 36 19.3 0.3 0.00 3.098 3.6 2.761 186 1 0.95 17.94 645.75

2 114 19.3 0.3 0.17 3.098 3.6 2.761 186 1 0.9 45.04 5134.08

3 36 19.3 0.3 0.00 3.098 3.6 2.761 186 1 0.79 17.94 645.75

4 114 19.3 0.3 0.16 3.098 3.6 2.761 186 1 1.34 56.54 6445.12

Roof 549 7.9 0.86 0.00 7.141 48.52 26646.90

OTTV 46.53

Table 07: OTTV of the modified building 1

1.2.3. Annual cooling energy





Introduce wall with insulation

1.3.1. U values of the wall material

Wall thicknesses were increased and insulations were introduced to walls to reduce the OTTV. Following

table and Figure shows the properties of the modified wall.


W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm


Brick, burned 0.85 840 1500 112

EPS Expanded Polystyrene 0.72 840 1860 15

Brick, burned 0.85 840 1500 112


Uw , W/m2.K 1.251

Table 08: Properties and U value of modified wall of the building 1(Adapted from DesignBuilder)

56

Figure 04: Layout diagram of modified wall of building 1 (Adapted from DesignBuilder)



Wall


1 36 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.95 7.24 260.76

2 114 19.3 0.3 0.17 1.251 3.6 6.257 186 1 0.9 38.30 4366.11

3 36 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.79 7.24 260.76

4 114 19.3 0.3 0.16 1.251 3.6 6.257 186 1 1.34 49.57 5650.61

Roof 549 7.9 0.86 0.00 7.141 48.52 26646.90

OTTV 43.8







Introduction of tile for roof

1.4.1 U values of the tiles

It has introduced the clay tile as the roof material. Following table shows the properties of the clay tile.

57

Roof material Conductivity,

W/m.k

Specific

Heat,

J/kg.K

Density,

kg/m3 Thickness, mm

Clay tile 1 800 2000 2

Uw , W/m2.K 7.042

Table 10: Properties and U value of modified roof of the building 1(Adapted from DesignBuilder)

Following Figure shows the layout diagram of the modified roof.

Figure 05: Layout diagram of modified roof of building 1 (Adapted from DesignBuilder)




1 36 19.3 0.3 0.00 3.098 3.6 6.257 186 1 0.95 17.937 645.747

2 114 19.3 0.3 0.17 3.098 3.6 6.257 186 1 0.9 47.175 5377.989

3 36 19.3 0.3 0.00 3.098 3.6 6.257 186 1 0.79 17.937 645.747

4 114 19.3 0.3 0.16 3.098 3.6 6.257 186 1 1.34 58.550 6674.685

Roof 549 7.9 0.86 0.00 7.042 47.843 26277.480

OTTV 46.70






58


Introduce insulations to walls and roof, in order to achieve the

maximum U values for facades and roofs specified in Building Code

1.5.1 U values of the wall and roof materials

Insulation layer was introduced to building wall to achieve the maximum U value specified in the code.

Following table shows the conductivity, specific heat, density, thickness and U value of the modified wall.


W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Brick Work 0.84 800 1700 100

XPS Extruded polystyrene –

CO2 blowing 0.034 1400 35 58

Concrete Block 0.51 1000 1400 100


Uw, W/m2.K 0.45

Table 12: Properties and U value of modified wall construction of the building 1 (Adapted from

DesignBuilder)

Following Figure shows a cross section of a modified wall.

Figure 06: Cross section of the modified wall of building 1(Adapted from DesignBuilder)

Clay tile was introduced to building roof. Following table shows the conductivity, specific heat, density,

thickness and U value of the modified roof.

59

Roof materials Conductivity,

W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Clay tile 1 800 2000 25

MW Stone Wool 0.04 840 30 125

Roofing felt 0.19 837 960 5

Uw , W/m2.K 0.302

Table 13: Properties and U value of modified roof construction of the building 1 (Adapted from

DesignBuilder)

Following Figure shows a cross section of a modified roof.

Figure 07: Cross section of the modified roof of building 1(Adapted from DesignBuilder)




1 36 19.3 0.3 0.00 0.45 3.6 6.257 186 1 0.95 2.61 93.80

2 114 19.3 0.3 0.17 0.45 3.6 6.257 186 1 0.9 34.45 3927.28

3 36 19.3 0.3 0.00 0.45 3.6 6.257 186 1 0.79 2.61 93.80

4 114 19.3 0.3 0.16 0.45 3.6 6.257 186 1 1.34 45.67 5206.50

Roof 549 7.9 0.86 0.00 0.30 2.04 1119.46

OTTV 12.29


60






Reduction of WWR

1.6.1 U values of the construction materials

U values of the construction materials are same as section 1.1.1.


While WWR of the East and West facades were reduced, North and south facades were increased.



1 36 19.3 0.3 0.07 3.098 3.6 6.257 186 1 0.95 29.721 1069.961

2 114 19.3 0.3 0.15 3.098 3.6 6.257 186 1 0.9 43.027 4905.023

3 36 19.3 0.3 0.01 3.098 3.6 6.257 186 1 0.79 18.990 683.629

4 114 19.3 0.3 0.14 3.098 3.6 6.257 186 1 1.34 53.607 6111.187

Roof 549.24 7.9 0.86 0.000 7.141 48.516 26646.903

OTTV 46.4







Reduction of WWR and Introduction of 1m overhang to windows



61


Further to modifications carried out in section 1.6, overhangs with 1m length were introduced. Following

table shows the OTTV of the modified building.


1 36 19.3 0.3 0.07 3.098 3.6 6.257 186

0.39 0.95 22.71 817.74

2 114 19.3 0.3 0.15 3.098 3.6 6.257 186

0.43 0.90 29.11 3318.22

3 36 19.3 0.3 0.01 3.098 3.6 6.257 186

0.59 0.79 18.57 668.57

4 114 19.3 0.3 0.14 3.098 3.6 6.257 186

0.50 1.34 36.09 4114.77

Roof 549.24 7.9 0.86 0.000 7.141

48.52 26646.90

OTTV 41.9







Reduction of WWR, Introduction of 1m overhang to windows and

introduction of brick for walls


Further to modifications carried out in section 1.7, burned bricks were introduced to building wall to

reduce the U value. U values of roof and window materials are same as section 1.1.1. Following table

shows the conductivity, specific heat, density, thickness and U value of the modified wall.


W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm


Cement plaster, sand aggregate 0.72 840 1860 10

Burned Brick 0.72 840 1920 110

Cement plaster, sand aggregate 0.72 840 1860 10


Uw, W/m2.K 2.813

Table 17: Properties and U value of modified wall construction of the building 1 (Adapted from

DesignBuilder)

62

Following Figure shows a cross section of a modified wall.

Figure 08: Cross section of the modified wall of building 1(Adapted from DesignBuilder)




1 36 19.3 0.3 0.07 2.813 3.6 6.257 186

0.39 0.95 21.17 762.19

2 114 19.3 0.3 0.15 2.813 3.6 6.257 186

0.43 0.9 27.70 3157.55

3 36 19.3 0.3 0.01 2.813 3.6 6.257 186

0.59 0.79 16.93 609.57

4 114 19.3 0.3 0.14 2.813 3.6 6.257 186

0.5 1.34 34.68 3953.09

Roof 549.24 7.9 0.86 0.000 7.141

48.52 26646.90

OTTV 41.4






63


Reduction of WWR, Introduction of burned brick for wall and

Introduction of 1.5m overhang to windows




Further to modifications carried out in section 1.8, length of overhangs was lengthening to 1.5m.



1 36 19.3 0.3 0.07 3.098 3.6 6.257 186

0.37 0.95 20.94 753.93

2 114 19.3 0.3 0.15 3.098 3.6 6.257 186

0.36 0.90 25.87 2948.76

3 36 19.3 0.3 0.01 3.098 3.6 6.257 186

0.37 0.79 16.70 601.31

4 114 19.3 0.3 0.14 3.098 3.6 6.257 186

0.54 1.34 35.90 4092.84

Roof 549.24 7.9 0.86 0.000 7.141

48.52 26646.90

OTTV 41.3







Reduction of WWR, Introduction of burned brick for wall and

Introduction of 1.5m overhang to windows


Further to modifications carried out in section 1.9, clay tiles were introduced for roof. U values of the

construction materials are same as section 1.9.1 except roofing materials. Following table shows the

conductivity, specific heat, density, thickness and U value of the modified roof.

64


W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Clay tile 1 800 2000 25

Uw , W/m2.K 6.061


DesignBuilder)

Figure 09: Cross section of the modified roof of building 1(Adapted from DesignBuilder)




1 36 19.3 0.3 0.07 3.098 3.6 6.257 186 0.37 0.95 20.94 753.93

2 114 19.3 0.3 0.15 3.098 3.6 6.257 186 0.36 0.90 25.87 2948.76

3 36 19.3 0.3 0.01 3.098 3.6 6.257 186 0.37 0.79 16.70 601.31

4 114 19.3 0.3 0.14 3.098 3.6 6.257 186 0.54 1.34 35.90 4092.84

Roof 549.24 7.9 0.86 0.00 6.061 41.18 22616.84

OTTV 36.5






65

2. Building 2: Wing 4 G of Bandaranayke Memorial

International Conference Hall (BMICH)


2.1.1 U values of the building construction materials


construction material for each element. Following table shows the conductivity, specific heat, density and

thickness of the each layer of the wall construction and U value of the wall.


W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm



Brick 0.72 840 1650 225



Uw , W/m2.K 1.796

Table 21: Properties of Existing Construction Materials and U value of the wall of building 2



Figure 10: Cross section of the wall of building 2 (Adapted from DesignBuilder)

Single layer, 3mm thick glass are used for the windows and following table shows the conductivity and U

value of the glass.

66



Uf, W/m2.K 6.257



The roofing material and properties are shown in below;

Material Conductivity,

W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Asphalt 0.7 1000 2100 2

Concrete , cast-roofing slab

,aerate 0.16 840 500 100

U, W/m2.K 1.302

Table 23: Properties and U value of existing roof construction materials of the building 2 (Adapted

from DesignBuilder)

Following Figure shows a cross section of a roof of existing building

Figure 11: Cross section of the roof of building 2 (Adapted from DesignBuilder)

The floor construction material and properties are shown in below table;

Table 24: Properties and U value of Existing floor Construction Materials of the building 2


Conductivity,

W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Floor/ Roof Screed 0.41 840 1200 70

Cast Concrete 1.13 1000 2000 100

U, W/m2.K 7.141

67

2.1.2. Calculation of Window to Wall Ratio (WWR)


the Figure for OTTV calculation. WWR of faces were calculated based on measured data. All floors are

identical.

Figurer 12: Layout diagram of building 2 (Adapted from DesignBuilder)

WWR of Wall face 1 of ground floor

Number of Windows = 12

Area of Window = 2.06 m2

Total Window area = 12*2.06

=24.7 m2

Total Wall Area = 47*3.68

=171.5 m2

WWR

= 24.7/171.5

=0.14

This method was followed to find the WWR of other faces also.

68

2.1.3. Calculation of shading coefficient of windows

It is considered the shading due to the verandah in wall faces 1 and 3.

Length of the verandah (Depth of Horizontal Projection) = 1.25 m

Height of the window

= 2.22 m

R1

= 1.25/2.22

=0.6

The OTTV value for the existing building was calculated using above U values, R1 and calculated WWR.

Below table shows the calculation of OTTVs for each building component.

Floor

No.

Wall


Ground

1 171.49 19.3 0.30 0.14 1.80 3.60 6.257 186 0.56 0.79 24.00 4114.89

2 40.41 19.3 0.30 0.00 1.80 3.60 6.257 186 0.47 0.90 10.40 420.18

3 171.49 19.3 0.30 0.45 1.80 3.60 6.257 186 0.52 0.79 49.86 8550.90

4 40.41 19.3 0.30 0.00 1.80 3.60 6.257 186 0.61 1.34 10.40 420.18

First

1 171.49 19.3 0.30 0.14 1.80 3.60 6.257 186 0.56 0.79 24.00 4114.89

2 40.41 19.3 0.30 0.00 1.80 3.60 6.257 186 0.47 0.90 10.40 420.18

3 171.49 19.3 0.30 0.45 1.80 3.60 6.257 186 0.52 0.79 49.86 8550.90

4 40.41 19.3 0.30 0.00 1.80 3.60 6.257 186 0.61 1.34 10.40 420.18

Second

1 171.49 19.3 0.30 0.14 1.80 3.60 6.257 186 0.56 0.79 24.00 4114.89

2 40.41 19.3 0.30 0.00 1.80 3.60 6.257 186 0.47 0.90 10.40 420.18

3 171.49 19.3 0.30 0.45 1.80 3.60 6.257 186 0.52 0.79 49.86 8550.90

4 40.41 19.3 0.30 0.00 1.80 3.60 6.257 186 0.61 1.34 10.40 420.18

Roof 526.82 7.9 0.86 0.00 1.302

8.85 4660.14

OTTV 25.1

Table 25: Existing OTTV of the Building 2






Introduction of double layer glazing for the windows.


Double layer glasses were introduced to windows and the material properties are same as the section 1.2.1.

69


Below table show the calculation of OTTV of the building.

Floor No. Wall / Roof Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

Ground

1 171.49 19.3 0.30 0.14 1.8 3.6 2.76 186 0.56 0.79 21.85 3747.81

2 40.41 19.3 0.30 0.00 1.8 3.6 2.76 186 0.47 0.90 10.40 420.18

3 171.49 19.3 0.30 0.45 1.8 3.6 2.76 186 0.52 0.79 44.58 7644.27

4 40.41 19.3 0.30 0.00 1.8 3.6 2.76 186 0.61 1.34 10.40 420.18

First

1 171.49 19.3 0.30 0.14 1.8 3.6 2.76 186 0.56 0.79 21.85 3747.81

2 40.41 19.3 0.30 0.00 1.8 3.6 2.76 186 0.47 0.90 10.40 420.18

3 171.49 19.3 0.30 0.45 1.8 3.6 2.76 186 0.52 0.79 44.58 7644.27

4 40.41 19.3 0.30 0.00 1.8 3.6 2.76 186 0.61 1.34 10.40 420.18

Second

1 171.49 19.3 0.30 0.14 1.8 3.6 2.76 186 0.56 0.79 21.85 3747.81

2 40.41 19.3 0.30 0.00 1.8 3.6 2.76 186 0.47 0.90 10.40 420.18

3 171.49 19.3 0.30 0.45 1.8 3.6 2.76 186 0.52 0.79 44.58 7644.27

4 40.41 19.3 0.30 0.00 1.8 3.6 2.76 186 0.61 1.34 10.40 420.18

Roof 526.82 7.90 0.86 0.00 1.3 8.85 4660.14

OTTV 23.0



By simulating the revised parameters in the DesignBuilder software the annual cooling energy were found.

Annual Cooling energy = 419.23 MWh


Introduction of wall with insulation

2.3.1 U values of the wall material

Wall thicknesses were increased and insulations were introduced to walls to reduce the OTTV. Properties

of the modified wall are same as the section 1.2.2.


Below table shows the calculation of OTTVs of modified building.

70

Floor

No.

Wall /

Roof Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

Ground

1 171.49 19.3 0.3 0.14 1.251 3.6 6.257 186 0.56 0.79 20.90 3584.59

2 40.41 19.3 0.3 0.00 1.251 3.6 6.257 186 0.47 0.9 7.24 292.68

3 171.49 19.3 0.3 0.45 1.251 3.6 6.257 186 0.52 0.79 48.50 8317.87

4 40.41 19.3 0.3 0.00 1.251 3.6 6.257 186 0.61 1.34 7.24 292.68

First

1 171.49 19.3 0.3 0.14 1.251 3.6 6.257 186 0.56 0.79 20.90 3584.59

2 40.41 19.3 0.3 0.00 1.251 3.6 6.257 186 0.47 0.9 7.24 292.68

3 171.49 19.3 0.3 0.45 1.251 3.6 6.257 186 0.52 0.79 48.50 8317.87

4 40.41 19.3 0.3 0.00 1.251 3.6 6.257 186 0.61 1.34 7.24 292.68

Second

1 171.49 19.3 0.3 0.14 1.251 3.6 6.257 186 0.56 0.79 20.90 3584.59

2 40.41 19.3 0.3 0.00 1.251 3.6 6.257 186 0.47 0.9 7.24 292.68

3 171.49 19.3 0.3 0.45 1.251 3.6 6.257 186 0.52 0.79 48.50 8317.87

4 40.41 19.3 0.3 0.00 1.251 3.6 6.257 186 0.61 1.34 7.24 292.68

Roof 526.82 7.9 0.86 0.00 1.302 8.85 4660.14

OTTV 23.4


2.3.4 Annual cooling energy




Introduction of roof with insulation


Following table and Figure shows the properties of the modified roof.


W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Asphalt 0.7 1000 1200 19

Fiberboard 0.06 1000 300 13

XPS Extruded Polystyrene – CO2

blowing 0.034 1400 35 204.7

Cast concrete 0.38 1000 1200 100

Uw , W/m2.K 0.15

Table 22: Properties and U value of modified wall of the building 3 (Adapted from DesignBuilder)

71

Figure 13: Layout diagram of modified roof of building 3 (Adapted from DesignBuilder)



Floor

No. Wall / Roof Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

Ground

Floor

1 171 19.3 0.3 0.14 1.796 3.6 6.257 186 0.56 0.79 23.62 4049.97

2 40 19.3 0.3 0.00 1.796 3.6 6.257 186 0.47 0.9 10.40 420.18

3 171 19.3 0.3 0.45 1.796 3.6 6.257 186 0.52 0.79 50.24 8615.50

4 40 19.3 0.3 0.00 1.796 3.6 6.257 186 0.61 1.34 10.40 420.18

First

Floor

1 171 19.3 0.3 0.14 1.796 3.6 6.257 186 0.56 0.79 23.62 4049.97

2 40 19.3 0.3 0.00 1.796 3.6 6.257 186 0.47 0.9 10.40 420.18

3 171 19.3 0.3 0.45 1.796 3.6 6.257 186 0.52 0.79 50.24 8615.50

4 40 19.3 0.3 0.00 1.796 3.6 6.257 186 0.61 1.34 10.40 420.18

Second

Floor

1 171 19.3 0.3 0.14 1.796 3.6 6.257 186 0.56 0.79 23.62 4049.97

2 40 19.3 0.3 0.00 1.796 3.6 6.257 186 0.47 0.9 10.40 420.18

3 171 19.3 0.3 0.45 1.796 3.6 6.257 186 0.52 0.79 50.24 8615.50

4 40 19.3 0.3 0.00 1.796 3.6 6.257 186 0.61 1.34 10.40 420.18

Roof 527 7.9 0.86 0.00 0.150 1.02 536.88

OTTV 22.8





72





Insulation layer was introduced to building wall to achieve the maximum U value specified in the code.

The properties of the wall material are same as section 1.5.1.

Insulation layer was introduced to the roof and the Following table shows the conductivity, specific heat,

density, thickness and U value of the modified roof.


W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Asphalt 0.7 1000 1200 19

Fiberboard 0.06 1000 300 9

XPS Extruded Polystyrene – CO2

blowing 0.034 1400 35 65.2

Cast concrete 0.38 1000 1200 100

Uw , W/m2.K 0.4


DesignBuilder)

Following Figure shows a cross section of a modified roof.

Figure 14: Cross section of the modified roof of building 2 (Adapted from DesignBuilder)

73



Floor

No.

Wall

/

Roof

Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

Ground

Floor

1 171 19.3 0.3 0.14 0.45 3.6 6.257 186 0.56 0.79 17.32 2970.89

2 40 19.3 0.3 0.00 0.45 3.6 6.257 186 0.47 0.9 2.61 105.28

3 171 19.3 0.3 0.45 0.45 3.6 6.257 186 0.52 0.79 45.54 7810.16

4 40 19.3 0.3 0.00 0.45 3.6 6.257 186 0.61 1.34 2.61 105.28

First

Floor

1 171 19.3 0.3 0.14 0.45 3.6 6.257 186 0.56 0.79 17.32 2970.89

2 40 19.3 0.3 0.00 0.45 3.6 6.257 186 0.47 0.9 2.61 105.28

3 171 19.3 0.3 0.45 0.45 3.6 6.257 186 0.52 0.79 45.54 7810.16

4 40 19.3 0.3 0.00 0.45 3.6 6.257 186 0.61 1.34 2.61 105.28

Second

Floor

1 171 19.3 0.3 0.14 0.45 3.6 6.257 186 0.56 0.79 17.32 2970.89

2 40 19.3 0.3 0.00 0.45 3.6 6.257 186 0.47 0.9 2.61 105.28

3 171 19.3 0.3 0.45 0.45 3.6 6.257 186 0.52 0.79 45.54 7810.16

4 40 19.3 0.3 0.00 0.45 3.6 6.257 186 0.61 1.34 2.61 105.28

Roof 527 7.9 0.86 0.00 0.40 2.72 1431.69

OTTV 19.1




Annual Cooling energy = 428 MWh

2.6. OTTV and annual cooling energy for modified building: Reduce

WWR




The facades which have the WWR above 0.35, WWR of the facades were reduced as the maximum value

to 0.35. Below table shows the calculation of OTTVs for each building component.

74

Floor No.

Wall / Roof Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

Ground Floor

1 171.488 19.3 0.3 0.14 1.796 3.6 6.257 186 0.56 0.79 23.995 4114.894

2 40.4064 19.3 0.3 0.00 1.796 3.6 6.257 186 0.47 0.9 10.399 420.180

3 171.488 19.3 0.3 0.35 1.796 3.6 6.257 186 0.52 0.79 41.386 7097.227

4 40.4064 19.3 0.3 0.00 1.796 3.6 6.257 186 0.61 1.34 10.399 420.180

First Floor

1 171.488 19.3 0.3 0.14 1.796 3.6 6.257 186 0.56 0.79 23.995 4114.894

2 40.4064 19.3 0.3 0.00 1.796 3.6 6.257 186 0.47 0.9 10.399 420.180

3 171.488 19.3 0.3 0.35 1.796 3.6 6.257 186 0.52 0.79 41.386 7097.227

4 40.4064 19.3 0.3 0.00 1.796 3.6 6.257 186 0.61 1.34 10.399 420.180

Second Floor

1 171.488 19.3 0.3 0.14 1.796 3.6 6.257 186 0.56 0.79 23.995 4114.894

2 40.4064 19.3 0.3 0.00 1.796 3.6 6.257 186 0.47 0.9 10.399 420.180

3 171.488 19.3 0.3 0.35 1.796 3.6 6.257 186 0.52 0.79 41.386 7097.227

4 40.4064 19.3 0.3 0.00 1.796 3.6 6.257 186 0.61 1.34 10.399 420.180

0.000

Roof 526.82 7.9 0.86 0.00 1.302 8.846 4660.138

OTTV 22.7






WWR, Introduce double layer glazing for windows and insulations

to wall

Further to the modifications carried out in section 2.6, double layer glazings were introduced to the

window and insulations were introduced to walls in order to reduce the U values of window and wall.


U values of the window, wall and roof materials are same as in section 2.2.1, 1.2.2 and 2.1.1 respectively.



75

Floor No.

Wall / Roof Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

Ground Floor

1 171.49 19.30 0.30 0.14 1.251 3.60 2.761 186 0.56 0.79 19.48 3340.87

2 40.41 19.30 0.30 0.00 1.251 3.60 2.761 186 0.47 0.90 7.24 292.68

3 171.49 19.30 0.30 0.35 1.251 3.60 2.761 186 0.52 0.79 34.93 5990.09

4 40.41 19.30 0.30 0.00 1.251 3.60 2.761 186 0.61 1.34 7.24 292.68

First Floor

1 171.49 19.30 0.30 0.14 1.251 3.60 2.761 186 0.56 0.79 19.48 3340.87

2 40.41 19.30 0.30 0.00 1.251 3.60 2.761 186 0.47 0.90 7.24 292.68

3 171.49 19.30 0.30 0.35 1.251 3.60 2.761 186 0.52 0.79 34.93 5990.09

4 40.41 19.30 0.30 0.00 1.251 3.60 2.761 186 0.61 1.34 7.24 292.68

Second Floor

1 171.49 19.30 0.30 0.14 1.251 3.60 2.761 186 0.56 0.79 19.48 3340.87

2 40.41 19.30 0.30 0.00 1.251 3.60 2.761 186 0.47 0.90 7.24 292.68

3 171.49 19.30 0.30 0.35 1.251 3.60 2.761 186 0.52 0.79 34.93 5990.09

4 40.41 19.30 0.30 0.00 1.251 3.60 2.761 186 0.61 1.34 7.24 292.68

Roof 526.82 7.90 0.86 0.00 1.302 8.85 4660.14

OTTV 19.14





3. Building 3: Air- Mech Engineering Office Building



Properties of existing buildings’ wall, roof, windows and floor construction materials are same as the

section 2.1.1.



the Figure for OTTV calculation. WWR of faces were calculated based on measured data. First, Second

and third floors are identical.

76

Figure 16 Layout diagram of building 3 (Extracted from DesignBuilder)


Floor Wall/Roof Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

Ground

Floor

1 37 19.3 0.3 0.17 1.968 3.6 6.257 186 1 0.95 44 1626

2 55 19.3 0.3 0.00 1.968 3.6 6.257 186 1 0.9 11 631

3 37 19.3 0.3 0.03 1.968 3.6 6.257 186 1 0.79 15 568

4 55 19.3 0.3 0.11 1.968 3.6 6.257 186 1 1.34 39 2182

1st Floor

5 31 19.3 0.3 0.37 1.968 3.6 6.257 186 1 0.95 80 2442

6 21 19.3 0.3 0.00 1.968 3.6 6.257 186 1 0.9 11 243

7 8 19.3 0.3 0.55 1.968 3.6 6.257 186 1 0.79 98 798

8 11 19.3 0.3 0.40 1.968 3.6 6.257 186 1 0.9 83 924

9 8 19.3 0.3 0.55 1.968 3.6 6.257 186 1 0.95 115 931

10 12 19.3 0.3 0.00 1.968 3.6 6.257 186 1 0.9 11 139

11 31 19.3 0.3 0.25 1.968 3.6 6.257 186 1 0.79 50 1547

12 43 19.3 0.3 0.42 1.968 3.6 6.257 186 1 1.34 120 5137

2nd and

3rd Floors 330 24324

Roof 117 19.3 0.9 0.00 1.302 22 2586

OTTV 55.34

Table 28: Existing OTTV of the Building 3

77






Introduce double layer glazing for the windows.




Below table show the calculation of OTTV of the building.

Floor

Wall

/Roo

f


Ground

Floor

1 37 19.3 0.3 0.17 1.968 3.6 2.761 186 1 0.95 42 1545

2 55 19.3 0.3 0.00 1.968 3.6 2.761 186 1 0.9 11 631

3 37 19.3 0.3 0.03 1.968 3.6 2.761 186 1 0.79 15 556

4 55 19.3 0.3 0.11 1.968 3.6 2.761 186 1 1.34 38 2107

1st Floor

5 31 19.3 0.3 0.37 1.968 3.6 2.761 186 1 0.95 75 2302

6 21 19.3 0.3 0.00 1.968 3.6 2.761 186 1 0.9 11 243

7 8 19.3 0.3 0.55 1.968 3.6 2.761 186 1 0.79 91 742

8 11 19.3 0.3 0.40 1.968 3.6 2.761 186 1 0.9 78 868

9 8 19.3 0.3 0.55 1.968 3.6 2.761 186 1 0.95 108 875

10 12 19.3 0.3 0.00 1.968 3.6 2.761 186 1 0.9 11 139

11 31 19.3 0.3 0.25 1.968 3.6 2.761 186 1 0.79 47 1452

12 43 19.3 0.3 0.42 1.968 3.6 2.761 186 1 1.34 115 4912

2nd and

3rd Floors 330 23066

Roof 117 19.3 0.88 0.00 1.302 22 2586

OTTV 52.76






78









Ground

Floor

1 37 19.3 0.3 0.17 1.251 3.6 6.257 186 1 0.95 41 1499

2 55 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7 401

3 37 19.3 0.3 0.03 1.251 3.6 6.257 186 1 0.79 11 418

4 55 19.3 0.3 0.11 1.251 3.6 6.257 186 1 1.34 36 1976

1st Floor

5 31 19.3 0.3 0.37 1.251 3.6 6.257 186 1 0.95 77 2362

6 21 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7 154

7 8 19.3 0.3 0.55 1.251 3.6 6.257 186 1 0.79 97 783

8 11 19.3 0.3 0.40 1.251 3.6 6.257 186 1 0.9 80 897

9 8 19.3 0.3 0.55 1.251 3.6 6.257 186 1 0.95 113 916

10 12 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7 88

11 31 19.3 0.3 0.25 1.251 3.6 6.257 186 1 0.79 47 1451

12 43 19.3 0.3 0.42 1.251 3.6 6.257 186 1 1.34 118 5034

2nd and 3rd

Floors 330 23369

Roof 117 19.3 0.88 0.00 1.302 22 2586

OTTV 52.65








3.4.1 U values of the roof material

Insulations were introduced to roofs to reduce the OTTV. Properties of the modified roof are same as the

section 1.2.2.



79


Ground

Floor

1 37 19.3 0.3 0.17 1.968 3.6 6.257 186 1 0.95 44 1626

2 55 19.3 0.3 0.00 1.968 3.6 6.257 186 1 0.9 11 631

3 37 19.3 0.3 0.03 1.968 3.6 6.257 186 1 0.79 15 568

4 55 19.3 0.3 0.11 1.968 3.6 6.257 186 1 1.34 39 2182

1st

Floor

5 31 19.3 0.3 0.37 1.968 3.6 6.257 186 1 0.95 80 2442

6 21 19.3 0.3 0.00 1.968 3.6 6.257 186 1 0.9 11 243

7 8 19.3 0.3 0.55 1.968 3.6 6.257 186 1 0.79 98 798

8 11 19.3 0.3 0.40 1.968 3.6 6.257 186 1 0.9 83 924

9 8 19.3 0.3 0.55 1.968 3.6 6.257 186 1 0.95 115 931

10 12 19.3 0.3 0.00 1.968 3.6 6.257 186 1 0.9 11 139

11 31 19.3 0.3 0.25 1.968 3.6 6.257 186 1 0.79 50 1547

12 43 19.3 0.3 0.42 1.968 3.6 6.257 186 1 1.34 120 5137

2nd and

3rd

Floors

330 24324

Roof 117 19.3 0.88 0.00 0.15 3 298

OTTV 52.47










Insulation layers were introduced to building wall and roof to achieve the maximum U value specified in

the code. The properties of these materials are same as section 2.5.1.



80


Ground

Floor

1 37 19.3 0.3 0.17 0.45 3.6 6.257 186 1 0.95 37 1357

2 55 19.3 0.3 0.00 0.45 3.6 6.257 186 1 0.9 3 144

3 37 19.3 0.3 0.03 0.45 3.6 6.257 186 1 0.79 7 251

4 55 19.3 0.3 0.11 0.45 3.6 6.257 186 1 1.34 32 1747

1st Floor

5 31 19.3 0.3 0.37 0.45 3.6 6.257 186 1 0.95 74 2272

6 21 19.3 0.3 0.00 0.45 3.6 6.257 186 1 0.9 3 56

7 8 19.3 0.3 0.55 0.45 3.6 6.257 186 1 0.79 94 766

8 11 19.3 0.3 0.40 0.45 3.6 6.257 186 1 0.9 78 866

9 8 19.3 0.3 0.55 0.45 3.6 6.257 186 1 0.95 111 899

10 12 19.3 0.3 0.00 0.45 3.6 6.257 186 1 0.9 3 32

11 31 19.3 0.3 0.25 0.45 3.6 6.257 186 1 0.79 44 1343

12 43 19.3 0.3 0.42 0.45 3.6 6.257 186 1 1.34 115 4919

2,3 330 22303

Roof 117 19.3 0.88 0.00 0.40 7 794

OTTV 47.40







Introduce insulations to walls and roof


Insulation layers were introduced to building wall and roof. The properties of wall and roof materials are

same as section 3.3.1 and 3.4.1 respectively.



81


Ground Floor

1 37 19.3 0.3 0.17 1.251 3.6 6.257 186 1 0.95 40.54 1498.67

2 55 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7.24 401.37

3 37 19.3 0.3 0.03 1.251 3.6 6.257 186 1 0.79 11.31 418.17

4 55 19.3 0.3 0.11 1.251 3.6 6.257 186 1 1.34 35.66 1976.23

1st Floor

5 31 19.3 0.3 0.37 1.251 3.6 6.257 186 1 0.95 77.44 2361.77

6 21 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7.24 154.42

7 8 19.3 0.3 0.55 1.251 3.6 6.257 186 1 0.79 96.53 783.12

8 11 19.3 0.3 0.40 1.251 3.6 6.257 186 1 0.9 80.32 896.57

9 8 19.3 0.3 0.55 1.251 3.6 6.257 186 1 0.95 112.91 916.00

10 12 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7.24 88.37

11 31 19.3 0.3 0.25 1.251 3.6 6.257 186 1 0.79 47.09 1450.61

12 43 19.3 0.3 0.42 1.251 3.6 6.257 186 1 1.34 117.89 5033.86

2nd and 3rd floors

330

23369.45

Roof 117 19.3 0.88 0.00 0.15

2.55 297.90

OTTV 49.78







Introduce insulations to walls and roof and reduce WWR

Further to the modifications carried out in section 3.6, facades which have the WWR above 0.35, WWR

of the facades were reduced as the maximum value to 0.35.


Insulation layers were introduced to building wall and roof. The properties of wall and roof materials are

same as section 3.3.1 and 3.4.1 respectively.



82


Ground Floor

1 37 19.3 0.3 0.17 1.251 3.6 6.257 186 1 0.95 41 1499

2 55 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7 401

3 37 19.3 0.3 0.03 1.251 3.6 6.257 186 1 0.79 11 418

4 55 19.3 0.3 0.11 1.251 3.6 6.257 186 1 1.34 36 1976

1st Floor

5 31 19.3 0.3 0.35 1.251 3.6 6.257 186 1 0.95 74 2270

6 21 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7 154

7 8 19.3 0.3 0.35 1.251 3.6 6.257 186 1 0.79 64 519

8 11 19.3 0.3 0.35 1.251 3.6 6.257 186 1 0.9 71 795

9 8 19.3 0.3 0.35 1.251 3.6 6.257 186 1 0.95 74 604

10 12 19.3 0.3 0.00 1.251 3.6 6.257 186 1 0.9 7 88

11 31 19.3 0.3 0.25 1.251 3.6 6.257 186 1 0.79 47 1451

12 43 19.3 0.3 0.35 1.251 3.6 6.257 186 1 1.34 100 4263

2,3

330

20288

Roof 117 19.3 0.88 0.00 0.15

3 298

OTTV 43.98







Introduce insulations to walls and roof, reduce WWR and

introduce 1m length overhangs to windows

Further to the modifications carried out in section 3.7, 1m length overhangs were introduced to windows


The properties of wall and roof materials are same as section 3.3.1 and 3.4.1 respectively.



83


Ground Floor

1 37 19.3 0.3 0.17 1.251 3.6 6.257 186 0.53 0.95 26.14 966.19

2 55 19.3 0.3 0.00 1.251 3.6 6.257 186 0.59 0.9 7.24 401.37

3 37 19.3 0.3 0.03 1.251 3.6 6.257 186 0.68 0.79 10.13 374.57

4 55 19.3 0.3 0.11 1.251 3.6 6.257 186 0.68 1.34 27.09 1501.39

1st Floor

5 31 19.3 0.3 0.35 1.251 3.6 6.257 186 0.53 0.95 45.37 1383.78

6 21 19.3 0.3 0.00 1.251 3.6 6.257 186 0.59 0.9 7.24 154.42

7 8 19.3 0.3 0.35 1.251 3.6 6.257 186 0.68 0.79 47.56 385.88

8 11 19.3 0.3 0.35 1.251 3.6 6.257 186 0.59 0.9 47.16 526.45

9 8 19.3 0.3 0.35 1.251 3.6 6.257 186 0.53 0.95 54.65 443.35

10 12 19.3 0.3 0.00 1.251 3.6 6.257 186 0.59 0.9 7.24 88.37

11 31 19.3 0.3 0.25 1.251 3.6 6.257 186 0.68 0.79 30.13 928.04

12 43 19.3 0.3 0.35 1.251 3.6 6.257 186 0.68 1.34 64.06 2735.36

2nd and 3rd floors

330

13291.31

Roof 117 19.3 0.88 0.00 0.15

2.55 298

OTTV 29.48






4. Building 4: Sri Lanka Standards Institute (SLSI) Building



Properties of existing buildings’ wall, roof, windows and floor construction materials are same as the

section 2.1.1.


Following Figure shows the plan view of the building. It has numbered the wall faces as indicate in the

Figure for OTTV calculation.

84

Figure 18: Plan view of building 4

Note: Not drawn to the scale

Following Figure shows the layout diagram of the building 4 used for DesignBuilder software. It indicates

the wall face 1 and 17. All floors are identical. WWR of faces were calculated based on measured data.

Figure 19: Layout diagram of building 4

Following table shows the calculation of OTTV.

85

Floor Wall


Ground

Floor

1 32 19.3 0.57 0.40 1.968 3.6 6.257 186 0.45 0.95 54 1,723

2 4 19.3 0.57 - 1.968 3.6 6.257 186 0.50 0.90 22 91

3 32 19.3 0.57 0.40 1.968 3.6 6.257 186 0.45 0.95 54 1,711

4 4 19.3 0.57 - 1.968 3.6 6.257 186 0.58 1.34 22 91

5 16 19.3 0.57 0.40 1.968 3.6 6.257 186 0.45 0.95 54 862

6 12 19.3 0.57 - 1.968 3.6 6.257 186 0.58 1.34 22 260

7 29 19.3 0.57 0.41 1.968 3.6 6.257 186 0.45 0.95 54 1,601

8 12 19.3 0.57 - 1.968 3.6 6.257 186 0.58 1.34 22 266

9 19 19.3 0.57 0.29 1.968 3.6 6.257 186 0.63 0.79 49 936

10 10 19.3 0.57 0.14 1.968 3.6 6.257 186 0.58 1.34 41 410

11 4 19.3 0.57 - 1.968 3.6 6.257 186 0.45 0.95 22 78

12 8 19.3 0.57 0.13 1.968 3.6 6.257 186 0.58 1.34 40 335

13 4 19.3 0.57 - 1.968 3.6 6.257 186 0.63 0.79 22 78

14 10 19.3 0.57 0.13 1.968 3.6 6.257 186 0.58 1.34 41 404

15 21 19.3 0.57 0.21 1.968 3.6 6.257 186 0.45 0.95 39 827

16 24 19.3 0.57 - 1.968 3.6 6.257 186 0.58 1.34 22 528

17 111 19.3 0.57 0.41 1.968 3.6 6.257 186 0.63 0.79 60 6,612

18 26 19.3 0.57 0.24 1.968 3.6 6.257 186 0.50 0.90 42 1,116

19 4 19.3 0.57 - 1.968 3.6 6.257 186 0.45 0.95 22 84

20 27 19.3 0.57 0.44 1.968 3.6 6.257 186 0.50 0.90 59 1,589

21 4 19.3 0.57 - 1.968 3.6 6.257 186 0.63 0.79 22 84

22 26 19.3 0.57 0.25 1.968 3.6 6.257 186 0.50 0.90 43 1,096

23 32 19.3 0.57 0.41 1.968 3.6 6.257 186 0.50 0.90 56 1,770

24 27 19.3 0.57 0.25 1.968 3.6 6.257 186 0.50 0.90 43 1,150

25 32 19.3 0.57 0.41 1.968 3.6 6.257 186 0.50 0.90 56 1,770

26 27 19.3 0.57 0.28 1.968 3.6 6.257 186 0.50 0.90 46 1,235

1,2,3,4,5,6,7

3896

186,971

Roof 768 19.3 0.88 0 1.302

22 16,973

OTTV 44.19





Annual cooling energy = 1.65 GWh





86



Floor

Wall

Face/

Roof


Ground

Floor

1 32 19.3 0.57 0.40 1.968 3.6 2.761 186 0.45 0.95 49 1,561

2 4 19.3 0.57 - 1.968 3.6 2.761 186 0.50 0.90 22 91

3 32 19.3 0.57 0.42 1.968 3.6 2.761 186 0.45 0.95 50 1,601

4 4 19.3 0.57 - 1.968 3.6 2.761 186 0.58 1.34 22 91

5 16 19.3 0.57 0.40 1.968 3.6 2.761 186 0.45 0.95 49 781

6 12 19.3 0.57 - 1.968 3.6 2.761 186 0.58 1.34 22 260

7 29 19.3 0.57 0.41 1.968 3.6 2.761 186 0.45 0.95 49 1,450

8 12 19.3 0.57 - 1.968 3.6 2.761 186 0.58 1.34 22 266

9 19 19.3 0.57 0.29 1.968 3.6 2.761 186 0.63 0.79 45 866

10 10 19.3 0.57 0.14 1.968 3.6 2.761 186 0.58 1.34 40 394

11 4 19.3 0.57 - 1.968 3.6 2.761 186 0.45 0.95 22 78

12 8 19.3 0.57 0.13 1.968 3.6 2.761 186 0.58 1.34 38 321

13 4 19.3 0.57 - 1.968 3.6 2.761 186 0.63 0.79 22 78

14 10 19.3 0.57 0.13 1.968 3.6 2.761 186 0.58 1.34 39 388

15 21 19.3 0.57 0.21 1.968 3.6 2.761 186 0.45 0.95 36 770

16 24 19.3 0.57 - 1.968 3.6 2.761 186 0.58 1.34 22 528

17 111 19.3 0.57 0.41 1.968 3.6 2.761 186 0.63 0.79 54 6,046

18 26 19.3 0.57 0.24 1.968 3.6 2.761 186 0.50 0.90 39 1,035

19 4 19.3 0.57 - 1.968 3.6 2.761 186 0.45 0.95 22 84

20 27 19.3 0.57 0.44 1.968 3.6 2.761 186 0.50 0.90 53 1,440

21 4 19.3 0.57 - 1.968 3.6 2.761 186 0.63 0.79 22 84

22 26 19.3 0.57 0.25 1.968 3.6 2.761 186 0.50 0.90 40 1,015

23 32 19.3 0.57 0.41 1.968 3.6 2.761 186 0.50 0.90 51 1,608

24 27 19.3 0.57 0.25 1.968 3.6 2.761 186 0.50 0.90 39 1,066

25 32 19.3 0.57 0.41 1.968 3.6 2.761 186 0.50 0.90 51 1,608

26 27 19.3 0.57 0.28 1.968 3.6 2.761 186 0.50 0.90 42 1,138

1,2,3,4,5

,6,7 3896

172,539

Roof 768 19.3 0.88 0 1.302

22 16,973

OTTV 41.03





nnual cooling energy = 1.66 GWh

87








Floor

Wall

Face/

Roof


Ground

Floor

1 32 19.3 0.57 0.40 1.251 3.6 6.257 186 0.45 0.95 49 1,574

2 4 19.3 0.57 - 1.251 3.6 6.257 186 0.50 0.9 14 58

3 32 19.3 0.57 0.42 1.251 3.6 6.257 186 0.45 0.95 51 1,625

4 4 19.3 0.57 - 1.251 3.6 6.257 186 0.58 1.34 14 58

5 16 19.3 0.57 0.40 1.251 3.6 6.257 186 0.45 0.95 49 787

6 12 19.3 0.57 - 1.251 3.6 6.257 186 0.58 1.34 14 165

7 29 19.3 0.57 0.41 1.251 3.6 6.257 186 0.45 0.95 50 1,464

8 12 19.3 0.57 - 1.251 3.6 6.257 186 0.58 1.34 14 169

9 19 19.3 0.57 0.29 1.251 3.6 6.257 186 0.63 0.79 43 829

10 10 19.3 0.57 0.14 1.251 3.6 6.257 186 0.58 1.34 35 343

11 4 19.3 0.57 - 1.251 3.6 6.257 186 0.45 0.95 14 50

12 8 19.3 0.57 0.13 1.251 3.6 6.257 186 0.58 1.34 33 277

13 4 19.3 0.57 - 1.251 3.6 6.257 186 0.63 0.79 14 50

14 10 19.3 0.57 0.13 1.251 3.6 6.257 186 0.58 1.34 34 336

15 21 19.3 0.57 0.21 1.251 3.6 6.257 186 0.45 0.95 33 695

16 24 19.3 0.57 - 1.251 3.6 6.257 186 0.58 1.34 14 335

17 111 19.3 0.57 0.41 1.251 3.6 6.257 186 0.63 0.79 55 6,092

18 26 19.3 0.57 0.24 1.251 3.6 6.257 186 0.50 0.9 36 958

19 4 19.3 0.57 - 1.251 3.6 6.257 186 0.45 0.95 14 54

20 27 19.3 0.57 0.44 1.251 3.6 6.257 186 0.50 0.9 54 1,470

21 4 19.3 0.57 - 1.251 3.6 6.257 186 0.63 0.79 14 54

22 26 19.3 0.57 0.25 1.251 3.6 6.257 186 0.50 0.9 37 946

23 32 19.3 0.57 0.41 1.251 3.6 6.257 186 0.50 0.9 52 1,624

24 27 19.3 0.57 0.25 1.251 3.6 6.257 186 0.50 0.9 37 990

25 32 19.3 0.57 0.41 1.251 3.6 6.257 186 0.50 0.9 52 1,624

26 27 19.3 0.57 0.28 1.251 3.6 6.257 186 0.50 0.9 40 1,083

1,2,3,4,5

,6,7 3896

165,957

Roof 768 19.3 0.88 0 1.302

22 16,973

OTTV 39.58





88






section 1.2.2.



89

Floor

Wall

Face/

Roof


Ground

Floor

1 32 19.3 0.57

0.40 1.968 3.6 6.257 186 0.45 0.95 49

1,546

2 4 19.3 0.57

- 1.968 3.6 6.257 186 0.5 0.9 22

91

3 32 19.3 0.57

0.42 1.968 3.6 6.257 186 0.45 0.95 48

1,533

4 4 19.3 0.57

- 1.968 3.6 6.257 186 0.58 1.34 22

91

5 16 19.3 0.57

0.40 1.968 3.6 6.257 186 0.45 0.95 49

773

6 12 19.3 0.57

- 1.968 3.6 6.257 186 0.58 1.34 22

260

7 29 19.3 0.57

0.41 1.968 3.6 6.257 186 0.45 0.95 49

1,427

8 12 19.3 0.57

- 1.968 3.6 6.257 186 0.58 1.34 22

266

9 19 19.3 0.57

0.29 1.968 3.6 6.257 186 0.63 0.79 49

936

10 10 19.3 0.57

0.14 1.968 3.6 6.257 186 0.58 1.34 41

410

11 4 19.3 0.57

- 1.968 3.6 6.257 186 0.45 0.95 22

78

12 8 19.3 0.57

0.13 1.968 3.6 6.257 186 0.58 1.34 40

335

13 4 19.3 0.57

- 1.968 3.6 6.257 186 0.63 0.79 22

78

14 10 19.3 0.57

0.13 1.968 3.6 6.257 186 0.58 1.34 41

404

15 21 19.3 0.57

0.21 1.968 3.6 6.257 186 0.45 0.95 39

827

16 24 19.3 0.57

- 1.968 3.6 6.257 186 0.58 1.34 22

528

17 111 19.3 0.57

0.41 1.968 3.6 6.257 186 0.63 0.79 53

5,899

18 26 19.3 0.57

0.24 1.968 3.6 6.257 186 0.5 0.9 42

1,116

19 4 19.3 0.57 - 1.968 3.6 6.257 186 0.45 0.95 22

84

20 27 19.3 0.57 0.44 1.968 3.6 6.257 186 0.5 0.9 59

1,589

21 4 19.3 0.57 - 1.968 3.6 6.257 186 0.63 0.79 22

84

22 26 19.3 0.57 0.25 1.968 3.6 6.257 186 0.5 0.9 43

1,096

23 32 19.3 0.57 0.41 1.968 3.6 6.257 186 0.5 0.9 50

1,574

24 27 19.3 0.57 0.25 1.968 3.6 6.257 186 0.5 0.9 43

1,150

25 32 19.3 0.57 0.41 1.968 3.6 6.257 186 0.5 0.9 50

1,574

26 27 19.3 0.57 0.28 1.968 3.6 6.257 186 0.5 0.9 46

1,235

1,2,3,4,5

,6,7 3896

174,900

Roof 768 19.3 0.88 0 0.15 3

1,955

OTTV 39


90









Insulation layers were introduced to building wall and roof to achieve the maximum U value specified in

the code. The properties of these materials are same as section 2.5.1.



91

Floor

Wall

Face/

Roof


Ground

Floor

1 32 19.3 0.57 0.4 0.45 3.6 6.257 186 0.45 0.95 44 1407

2 4 19.3 0.57 0 0.45 3.6 6.257 186 0.5 0.9 5 21

3 32 19.3 0.57 0.4 0.45 3.6 6.257 186 0.45 0.95 44 1392

4 4 19.3 0.57 0 0.45 3.6 6.257 186 0.58 1.34 5 21

5 16 19.3 0.57 0.4 0.45 3.6 6.257 186 0.45 0.95 44 703

6 12 19.3 0.57 0 0.45 3.6 6.257 186 0.58 1.34 5 59

7 29 19.3 0.57 0.4 0.45 3.6 6.257 186 0.45 0.95 45 1311

8 12 19.3 0.57 0 0.45 3.6 6.257 186 0.58 1.34 5 61

9 19 19.3 0.57 0.3 0.45 3.6 6.257 186 0.63 0.79 37 708

10 10 19.3 0.57 0.1 0.45 3.6 6.257 186 0.58 1.34 27 268

11 4 19.3 0.57 0 0.45 3.6 6.257 186 0.45 0.95 5 18

12 8 19.3 0.57 0.1 0.45 3.6 6.257 186 0.58 1.34 25 212

13 4 19.3 0.57 0 0.45 3.6 6.257 186 0.63 0.79 5 18

14 10 19.3 0.57 0.1 0.45 3.6 6.257 186 0.58 1.34 26 260

15 21 19.3 0.57 0.2 0.45 3.6 6.257 186 0.45 0.95 26 548

16 24 19.3 0.57 0 0.45 3.6 6.257 186 0.58 1.34 5 121

17 111 19.3 0.57 0.4 0.45 3.6 6.257 186 0.63 0.79 50 5511

18 26 19.3 0.57 0.2 0.45 3.6 6.257 186 0.5 0.9 30 782

19 4 19.3 0.57 0 0.45 3.6 6.257 186 0.45 0.95 5 19

20 27 19.3 0.57 0.4 0.45 3.6 6.257 186 0.5 0.9 50 1337

21 4 19.3 0.57 0 0.45 3.6 6.257 186 0.63 0.79 5 19

22 26 19.3 0.57 0.2 0.45 3.6 6.257 186 0.5 0.9 31 778

23 32 19.3 0.57 0.4 0.45 3.6 6.257 186 0.5 0.9 46 1459

24 27 19.3 0.57 0.2 0.45 3.6 6.257 186 0.5 0.9 30 811

25 32 19.3 0.57 0.4 0.45 3.6 6.257 186 0.5 0.9 46 1459

26 27 19.3 0.57 0.3 0.45 3.6 6.257 186 0.5 0.9 34 913

1,2,3,4,5

,6,7 3896 141521

Roof 768 19.3 0.88 0 0.4 7 5214

OTTV 32






92


WWR

The facades which have the WWR above 0.3, WWR of the facades were reduced as the maximum value to

0.3.

4.6.1 U values of construction materials

Properties of the buildings’ wall, roof, windows and floor construction materials are same as the section

2.1.1.



93

Floor Wall

Face/Roof


Ground Floor

1 32 19.3 0.57 0.30 1.968 3.6 6.257 186 0.45 0.95 46 1,455

2 4 19.3 0.57 - 1.968 3.6 6.257 186 0.5 0.9 22 91

3 32 19.3 0.57 0.30 1.968 3.6 6.257 186 0.45 0.95 46 1,455

4 4 19.3 0.57 - 1.968 3.6 6.257 186 0.58 1.34 22 91

5 16 19.3 0.57 0.30 1.968 3.6 6.257 186 0.45 0.95 46 728

6 12 19.3 0.57 - 1.968 3.6 6.257 186 0.58 1.34 22 260

7 29 19.3 0.57 0.30 1.968 3.6 6.257 186 0.45 0.95 46 1,346

8 12 19.3 0.57 - 1.968 3.6 6.257 186 0.58 1.34 22 266

9 19 19.3 0.57 0.29 1.968 3.6 6.257 186 0.63 0.79 49 936

10 10 19.3 0.57 0.14 1.968 3.6 6.257 186 0.58 1.34 41 410

11 4 19.3 0.57 - 1.968 3.6 6.257 186 0.45 0.95 22 78

12 8 19.3 0.57 0.13 1.968 3.6 6.257 186 0.58 1.34 40 335

13 4 19.3 0.57 - 1.968 3.6 6.257 186 0.63 0.79 22 78

14 10 19.3 0.57 0.13 1.968 3.6 6.257 186 0.58 1.34 41 404

15 21 19.3 0.57 0.21 1.968 3.6 6.257 186 0.45 0.95 39 827

16 24 19.3 0.57 - 1.968 3.6 6.257 186 0.58 1.34 22 528

17 111 19.3 0.57 0.30 1.968 3.6 6.257 186 0.63 0.79 50 5,515

18 26 19.3 0.57 0.24 1.968 3.6 6.257 186 0.5 0.9 42 1,116

19 4 19.3 0.57 - 1.968 3.6 6.257 186 0.45 0.95 22 84

20 27 19.3 0.57 0.30 1.968 3.6 6.257 186 0.5 0.9 47 1,270

21 4 19.3 0.57 - 1.968 3.6 6.257 186 0.63 0.79 22 84

22 26 19.3 0.57 0.25 1.968 3.6 6.257 186 0.5 0.9 43 1,096

23 32 19.3 0.57 0.30 1.968 3.6 6.257 186 0.5 0.9 47 1,481

24 27 19.3 0.57 0.25 1.968 3.6 6.257 186 0.5 0.9 43 1,150

25 32 19.3 0.57 0.30 1.968 3.6 6.257 186 0.5 0.9 47 1,481

26 27 19.3 0.57 0.28 1.968 3.6 6.257 186 0.5 0.9 46 1,235

1,2,3,4,5,6,7

3896

166,608

Roof 768 19.3 0.88 0 1.302

22 16,973

OTTV 39.73







WWR and introduce insulations to walls

Further to the modifications at section 4.6, insulations were introduced to walls.

4.7.1 U values of construction materials

Properties of the buildings’ wall materials are same as the section 4.3.2.

94



Floor Wall

Face/Roof


Ground Floor

1 32 19.3 0.57 0.30 1.251 3.6 6.257 186 0.45 0.95 40.25 1,279.81

2 4 19.3 0.57 - 1.251 3.6 6.257 186 0.5 0.9 13.76 57.80

3 32 19.3 0.57 0.30 1.251 3.6 6.257 186 0.45 0.95 40.25 1,279.81

4 4 19.3 0.57 - 1.251 3.6 6.257 186 0.58 1.34 13.76 57.80

5 16 19.3 0.57 0.30 1.251 3.6 6.257 186 0.45 0.95 40.25 639.91

6 12 19.3 0.57 - 1.251 3.6 6.257 186 0.58 1.34 13.76 165.15

7 29 19.3 0.57 0.30 1.251 3.6 6.257 186 0.45 0.95 40.25 1,183.22

8 12 19.3 0.57 - 1.251 3.6 6.257 186 0.58 1.34 13.76 169.28

9 19 19.3 0.57 0.29 1.251 3.6 6.257 186 0.63 0.79 43.15 828.55

10 10 19.3 0.57 0.14 1.251 3.6 6.257 186 0.58 1.34 34.65 343.05

11 4 19.3 0.57 - 1.251 3.6 6.257 186 0.45 0.95 13.76 49.54

12 8 19.3 0.57 0.13 1.251 3.6 6.257 186 0.58 1.34 32.93 276.59

13 4 19.3 0.57 - 1.251 3.6 6.257 186 0.63 0.79 13.76 49.54

14 10 19.3 0.57 0.13 1.251 3.6 6.257 186 0.58 1.34 33.95 336.15

15 21 19.3 0.57 0.21 1.251 3.6 6.257 186 0.45 0.95 32.65 695.35

16 24 19.3 0.57 - 1.251 3.6 6.257 186 0.58 1.34 13.76 335.45

17 111 19.3 0.57 0.30 1.251 3.6 6.257 186 0.63 0.79 44.16 4,902.07

18 26 19.3 0.57 0.24 1.251 3.6 6.257 186 0.5 0.9 36.30 958.32

19 4 19.3 0.57 - 1.251 3.6 6.257 186 0.45 0.95 13.76 53.67

20 27 19.3 0.57 0.30 1.251 3.6 6.257 186 0.5 0.9 41.50 1,120.53

21 4 19.3 0.57 - 1.251 3.6 6.257 186 0.63 0.79 13.76 53.67

22 26 19.3 0.57 0.25 1.251 3.6 6.257 186 0.5 0.9 37.10 945.94

23 32 19.3 0.57 0.30 1.251 3.6 6.257 186 0.5 0.9 41.50 1,307.29

24 27 19.3 0.57 0.25 1.251 3.6 6.257 186 0.5 0.9 36.66 989.81

25 32 19.3 0.57 0.30 1.251 3.6 6.257 186 0.5 0.9 41.50 1,307.29

26 27 19.3 0.57 0.28 1.251 3.6 6.257 186 0.5 0.9 40.10 1,082.83

1,2,3,4,5,6,7

3896

143,278.97

Roof 768 19.3 0.88 0 1.302

22.11 16,973.07

OTTV 34.62






95

5. Building 5: World Trade Center (WTC) Building




construction material for each element.

Following table shows the conductivity, specific heat, density and thickness of the each layer of the wall

construction and U value of the wall.


W/m.K

Specific Heat,

J/kg.K

Density,

kg/m3

Thickness,

mm

Lightweight metallic cladding 0.29 1000 1250 6

Air layer

10

Concrete, Reinforced (with 1%

steel) 2.3 1000 2300 100

Cement plaster 0.72 840 1860 2


Uw , W/m2.K 2.37

Table 43: Properties of Existing Construction Materials and U value of the wall of building 5



Figure 20: Cross section of the wall of building 2 (Adapted from DesignBuilder)

96

Single layer, 6mm thick, blue colored glass are used for the windows and following table shows the

conductivity and U value of the glass.


Generic blue glass 0.9 6

Uf, W/m2.K 6.121



Properties of existing buildings’ roof and floor construction materials are same as the section 2.1.1.



97

Floor Wall Area ∆Teq α WWR Uw ∆T Uf SF SC CF OTTVi Ai*OTTVi

Level 1

1 340 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.95 83 28114

2 59 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.93 81 4829

3 74 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.9 79 5880

4 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.85 75 2547

5 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.79 71 2375

6 35 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3174

7 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 3701

8 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.85 75 2585

9 31 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.79 71 2169

10 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3018

11 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3072

12 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3037

13 35 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3175

14 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3037

15 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 3652

16 74 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 8315

Level 2,3 1216 109128

Level 4

1 114 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.95 83 9433

2 113 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.93 81 9175

3 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.85 75 2547

4 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.79 71 2375

5 35 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3174

6 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 3701

7 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.85 75 2585

8 31 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.79 71 2169

9 40 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 114 4522

10 113 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.95 88 9865

11 113 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 119 13446

12 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3018

13 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3072

14 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3037

15 35 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3175

16 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3037

17 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 3652

18 40 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3692

Level 5 - 37 30748 2830433

Roof 2092 19.3 0.88 0.0 1.302 22 46268

OTTV 87.8

Table 45: OTTV of the existing building 5

98




Annual cooling energy = 33200 MWh







99


Level 1

1 340 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.95 78 26471

2 59 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.93 76 4542

3 74 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.9 74 5520

4 34 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.85 71 2383

5 34 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.79 66 2213

6 35 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 3006

7 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.34 107 3541

8 34 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.85 71 2419

9 31 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.79 66 2021

10 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 2858

11 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 2910

12 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 2876

13 35 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 3007

14 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 2877

15 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.34 107 3494

16 74 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.34 107 7955

Level 2,3 1216 103245

Level 4

1 114 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.95 78 8882

2 113 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.93 76 8629

3 34 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.85 71 2383

4 34 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.79 66 2213

5 35 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 3006

6 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.34 107 3541

7 34 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.85 71 2419

8 31 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.79 66 2021

9 40 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.34 107 4234

10 113 19.3 0.12 0.40 2.373 3.6 2.761 186 1 0.95 78 8770

11 113 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.34 107 12071

12 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 2858

13 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 2910

14 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 2876

15 35 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 3007

16 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 2877

17 33 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.34 107 3494

18 40 19.3 0.12 0.40 2.373 3.6 2.761 186 1 1.07 87 3497

Level 5 - 37 30748 2629682

Roof 2092 19.3 0.88 0 1.302 22 46268

OTTV 81.8


100








Burned brick wall with insulations were introduced to walls to reduce the OTTV. Properties of the

modified wall are same as the section 1.2.2.



101


Level 1

1 340 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.95 81 27584

2 59 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.93 80 4737

3 74 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.9 78 5764

4 34 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.85 74 2494

5 34 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.79 69 2323

6 35 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 3120

7 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.34 110 3649

8 34 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.85 74 2531

9 31 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.79 69 2121

10 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 2966

11 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 3020

12 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 2985

13 35 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 3121

14 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 2985

15 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.34 110 3601

16 74 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.34 110 8199

Level 2,3

1895 162401

Level 4

1 114 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.95 81 9256

2 113 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.93 80 8999

3 34 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.85 74 2494

4 34 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.79 69 2323

5 35 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 3120

6 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.34 110 3649

7 34 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.85 74 2531

8 31 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.79 69 2121

9 40 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.34 110 4363

10 113 19.3 0.12 0.4 1.251 3.6 6.121 186 1 0.95 81 9139

11 113 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.34 110 12441

12 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 2966

13 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 3020

14 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 2985

15 35 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 3121

16 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 2985

17 33 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.34 110 3601

18 40 19.3 0.12 0.4 1.251 3.6 6.121 186 1 1.07 90 3629

Level 5 - 37

30748 2730512

Roof 2092 19.3 0.88 0 1.302 22 46268

OTTV 84.8


102









section 1.2.2.



103


Level 1

1 340 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.95 83 28114

2 59 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.93 81 4829

3 74 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.9 79 5880

4 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.85 75 2547

5 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.79 71 2375

6 35 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3174

7 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 3701

8 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.85 75 2585

9 31 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.79 71 2169

10 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3018

11 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3072

12 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3037

13 35 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3175

14 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3037

15 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 3652

16 74 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 8315

Level 2,3 1895 165356

Level 4

1 114 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.95 83 9433

2 113 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.93 81 9175

3 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.85 75 2547

4 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.79 71 2375

5 35 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3174

6 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 3701

7 34 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.85 75 2585

8 31 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.79 71 2169

9 40 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 4425

10 113 19.3 0.12 0.4 2.373 3.6 6.121 186 1 0.95 83 9314

11 113 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 12617

12 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3018

13 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3072

14 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3037

15 35 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3175

16 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3037

17 33 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.34 112 3652

18 40 19.3 0.12 0.4 2.373 3.6 6.121 186 1 1.07 92 3692

Level 5 - 37 30748 2778452

Roof 2092 19.3 0.88 0 0.15 3 5330

Total 36614 3116011

OTTV 85.1


104









Insulated building wall and roof were introduced to achieve the maximum U value specified in the code.

The properties of these materials are same as section 2.5.1.



105


1

1 340 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.95 80 27207

2 59 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.93 79 4671

3 74 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.9 76 5681

4 34 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.85 73 2457

5 34 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.79 68 2285

6 35 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 3081

7 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.34 109 3612

8 34 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.85 73 2493

9 31 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.79 68 2087

10 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 2930

11 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 2982

12 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 2948

13 35 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 3082

14 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 2948

15 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.34 109 3565

16 74 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.34 109 8116

2,3 1895 160292

4

1 114 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.95 80 9129

2 113 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.93 79 8873

3 34 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.85 73 2457

4 34 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.79 68 2285

5 35 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 3081

6 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.34 109 3612

7 34 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.85 73 2493

8 31 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.79 68 2087

9 40 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.34 109 4319

10 113 19.3 0.12 0.4 0.45 3.6 6.121 186 1 0.95 80 9013

11 113 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.34 109 12315

12 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 2930

13 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 2982

14 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 2948

15 35 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 3082

16 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 2948

17 33 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.34 109 3565

18 40 19.3 0.12 0.4 0.45 3.6 6.121 186 1 1.07 89 3584

5 - 37 30748 2696288

Roof 2092 19.3 0.88 0 0.4 7 14214

OTTV 82.8






106

ANNEXURE 2: Cost of Building Materials

Work item Unit Current Rate, Rs.

Reinforcement ton 106,049.44

Formwork m2 739.04

Wall materials

Brick work (225mm thick) m2 2,310.34

Brick work (112mm thick) m2 1,721.12

Block work (200 mm thick) m2 1,646.80



Internal Plastering m2 490.42

External Plastering m2 561.13

Glazing materials

Tempered Glass (5mm thick) m2 3,225.81





3mm Clear Glass m2 2,500.00

Dbl LoE (3mm/13mm Arg) Glass m2 5,250.00

Trp LoE Glass m2 7,875.00

Roofing materials

Concrete (Slab) m3 12,037.97

Cast Concrete (100mm thick) m2 1,203.80

SnAl Galvanized sheets (3' x 1') m2 645.16

Asbestos sheets (3.5' x 6') m2 576.04




Al Sheet m2 1,500.00

Clay tile (25*35) m2 800.00

Asphalt (19mm) m2 1,500.00

Roofing felt m2 100.00

Insulation materials

Mcfoil (2mm thick) m2 100.00

Mcfoil (3mm thick) m2 143.00

XPS foam board (205mm thick) m2 2,706.00

XPS foam board (65mm thick) m2 858.00

Fiber board (13mm thick) m2 855.00

Fiber board (9mm thick) m2 712.50

Analysis of Building Envelops to Optimize Energy...

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