Materials and Technologies for Green Construction

148 Pages·2014·12.57 MB·English

by  Mohammad Arif Kamal

Materials and Technologies
for Green Construction
Edited by
Mohammad Arif Kamal
Materials and Technologies
for Green Construction
Special topic volume with invited peer reviewed papers only.

Edited by
Mohammad Arif Kamal
Copyright  2015 Trans Tech Publications Ltd, Switzerland

All rights reserved. No part of the contents of this publication may be reproduced or
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Volume 632 of
Key Engineering Materials
ISSN print 1013-9826
ISSN cd 1662-9809
ISSN web 1662-9795

Full text available online at http://www.scientific.net

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PREFACE

Building construction is a major industry in every country and great deal of natural resources
are consumed in buildings. There is always a compounding pressure on resources due to
increasing pressure on consumption, especially on the energy front. The building and
construction activities worldwide consume 3 billion tons of raw materials each year or 40
percent of total global use. The buildings sector accounts for about 40% of primary energy
consumption, 70% of electricity use, and 40% of atmospheric emissions in developed
countries. Buildings are responsible for more than 40% carbon emission through embodied
energy in construction materials and products, energy consumed during construction process
and operational energy consumed by the buildings. In today’s contemporary architecture, the
key challenge is to choose materials and technologies that can reduce burden to the
environment. One of the key issues of sustainable development is the achievement of energy
efficiency. Using green building materials and products promotes conservation of dwindling
nonrenewable resources internationally. In addition, integrating green building materials into
building projects can help reduce the environmental impacts associated with the extraction,
transportation, processing, fabrication, installation, reuse, recycling, and disposal of these
building industry source materials. The need of the day is to have energy efficient buildings
materials and construction technologies that cater to the rising need hence alleviating pressure
on resources. Hence, selecting construction and finishing materials that have low embodied
energy and have less operational and maintenance cost is the most powerful tool for the
architects, designers and the constructors to achieve high energy efficiency in buildings. This
special volume on ‘Materials and Technologies for Green Construction’ contains Ten chapters
which address a wide range of issues pertaining to building materials and technologies with
reference to energy efficiency. This volume demonstrates that alternatives to modern building
materials are available and that today it is possible to produce building materials and select raw
materials from an ecological perspective.
Table of Contents
Preface
Insulating Materials for Energy Saving in Buildings
A. Kumar, R. Deoliya and P.S. Chani 1
Soil Based Building Materials for Energy Efficiency
S. Liuzzi and P. Stefanizzi 15
Glass-Wool Insulation: ECBC Compliance and Green Building Aspect
B. Roy 39
Energy Efficient Skylight Design in Tropical Houses
K.M. Al-Obaidi, M. Ismail and A.M. Abdul Rahman 45
Thermal Insulation System for Energy Efficiency
K.K. Mitra 57
Straw Bale: An Innovative Sustainable Material in Construction
A. Chaussinand 69
Fundamental Parameters of Heat and Moisture Transfer for Energy Efficiency in Buildings
S. Liuzzi and P. Stefanizzi 79
Energy Efficient Techniques for Construction: Planning of a Sustainable Community
K.S. Rakesh and M.P. Devaki 95
Recycling of Construction and Demolition Waste Material for Energy Savings in India
T.S. Brar, M.A. Kamal and P. Emerson 107
Drivers and their Relationship with Inhibitors Influencing the Adoption of Stabilized Earth
Construction to Alleviate Urban Housing Crisis in Zimbabwe
M.S. Zami 119
Key Engineering Materials Vol. 632 (2015) pp 1-14
© (2015) Trans Tech Publications, Switzerland
doi:10.4028/www.scientific.net/KEM.632.1
Insulating Materials for Energy Saving in Buildings
1, a 2,b 3,c
Ashok Kumar , Rajesh Deoliya and P.S.Chani
1Senior Principal Scientist & Head, Architecture & Planning,
CSIR-Central Building Research Institute, Roorkee, INDIA
2Principal Scientist, CSIR-Central Building Research Institute, Roorkee, INDIA
3 Associate Professor, Department of Architecture and Planning, IIT Roorkee, INDIA
a [email protected], b [email protected], [email protected]
Keywords: Thermal performance, Insulation, Walling materials, Roofing Technologies MATLAB
program, ECBC, NBC, Simulation, Thickness, U-factor, R-value
Abstract
Insulation is considered one of the effective solutions to achieve energy savings in buidings. Better
insulation having low thermal conductivity contributes significantly to new construction and
retrofitting existing buildings. The Energy Conservation Building Code and National Building Code
of India define the prescriptive and mandatory requirements for the U-factor and R-values for
different climates but the way to achieve these values is left to the designers. As none of the walling
and roofing assemblies in buildings fulfill the criteria for overall thermal transmittance, the study
deals with determining the thermal conductivity of sustainable walling materials and prefab roofing
technologies as well as insulating materials using Guarded Hot- Plate Apparatus. The MATLAB
program is developed for computing the U-values and for predicting the desired retrofit insulation
thicknesses to make different materials and roofing assembly combinations comply the Code
requirements in different climatic regions of India. The results of the study are used for computing
the performance with and without insulation using DesgnBuilder software for improving energy
efficinecy of the buildings in composite climate in India.
Introduction
Buildings have significant and continuously increasing impact on the environment because they are
responsible for a large portion of carbon emissions and use considerable amount of resources and
energy [1, 2]. Potentially, the most important environmental problem relating to energy utilization is
global climate change, also known as global warming. Currently, it is estimated that CO contributes
2
about 50% to the anthropogenic greenhouse effects [3-5]. As the heat flows through the walls and
roofs take a large part in the cooling / heating load of a building, the thermal performances have great
influences on the energy consumption and the thermal comfort of the room [6]. Existing buildings
built with conventional and prefab technologies between 1950 and 2005, that have a remaining
service life of 25 or more years represent enormous prospects of retrofitting to improve their overall
thermal performance. Therefore, there is enormous research being carried out on green building
retrofits throughout the world and is also one of the focus area of research at CSIR- Central Building
Research Institute (CBRI), Roorkee [7].

Heat transfer through walls and roofs is a function of indoor and outdoor temperatures, outside and
interior surfaces, heat transfer coefficients at the inner and outer surfaces, and solar radiation input on
the outer surfaces. The heat gain into a space is transient in nature primarily because of varying
ambient temperature and solar energy inputs [8]. The estimation of heat gain to a space through the
building envelope is the first step in calculating the cooling load [9].
Better insulation of low thermal conductivity is a significant contributor for new construction and
retrofitting existing buildings, when the emphasis is on energy efficiency as it contributes to achieve
2 Materials and Technologies for Green Construction
thermal comfort for its occupants for cold winters and warm summers in tropical climates. Insulation
makes a good economic sense as it reduces energy consumption in buildings and pays for itself many
times over during the life cycle of a building. Insulation reduces unwanted heat loss or gain and
decreases the energy demands of heating and cooling systems. The thermal insulation in walls and
roofs not only contributes in reducing the required air-conditioning system size but also in reducing
the annual energy cost in buildings. Additionally, it helps in extending the periods of thermal comfort
without reliance on mechanical air-conditioning especially during inter-seasons periods. It is
estimated that walls and roof insulation can produce energy savings up to 77% [7, 10 -12].

There are different types of insulation materials for applying on a new roof or retrofitting an existing
structure. The function of the roof insulation is to insulate the building against heat in flow from
outside during the day. The thermal conductance coefficients (U- factor) of the non-insulated roofs
range from 7.76 (250mm concrete) to 18.18 W/m² K (100mm concrete) [13]. Therefore, the heat
transfer within non-insulated roofs is greater than roofs with insulation. However, the magnitude of
energy savings as a result of using thermal insulation varies according to the building type, the
climatic conditions at which the building is located as well as the type, thickness, and location of the
insulating material used. A large number of insulation materials are used to slow heat loss, such as:
cellulose, fiberglass, rock wool, polystyrene, urethane foam, vermiculite. On the basis of temperature,
it can be categorized as, Low temperature insulation such as EPS, PUF, Glass wool, Expanded
Polyethylene etc. and high temperature insulation as Ceramic wool, Rock wool, Perlite Concrete etc.
The effectiveness of insulation is commonly evaluated by its R-value. However, an R-value does not
take into account the quality of construction or local environmental factors for each building. High
R-value enclosures reduce energy consumption for space heating in all the climatic zones. Their
impact is largest in climates with cold temperature for many hours, and smallest in climates with few
hours per year at cold temperatures. However, high R - value enclosures are still important for
enclosures exposed to the direct solar radiation in hot climates [7,14]. The studies conducted by
various researchers reveal that retrofitting by optimum insulation thickness is one of the effective
solutions to promote energy efficiency and sustainability of existing buildings [3, 7, 10 -12, 15-20].
But there are hardly any studies on improving thermal performance of buildings made of alternative
building materials and technologies developed during the past three - four decades and are being used
extensively in the building construction in India [7, 21].

Hence, the study presents computation of thermal resistance [R] and over all heat transfer coefficients
[U] by measuring the thermal conductivity of various walling and roofing materials used in buildings
and available insulating materials in India to achieve desired U-factor and R-value prescribed by
Energy Conservation Building Code (ECBC) and National Building Code (NBC) for diffeent
climatic zones designated as hot and dry, warm and humid, and composite [22 -23]. This research
study focuses on enhancement of thermal performance of different walling and roofing systems
developed by CSIR- CBRI and other institutions by applying retrofit insulation in existing buildings
for different climates covering major part of India to satisfy Code requirements from energy
conservation point of view.

Thermal Rating of Building Sections
Various investigations attempted by researchers across the world have used parameters like, U, Q / U
and damping for the assessment of thermal performance of building sections, applicable under steady
– state conditions. From these, it is possible to obtain a realistic comparison between different types
of building sections [9]. For arriving at a generic basis of thermal rating of building sections, the
computations of Thermal Conductivity (K) and Thermal Transmittance (U-factor) are prerequisites.
Thermal Conductivity is the quantity of heat in the steady state conditions flowing in unit time
through unit area of a slab of uniform material thickness of infinite extent and of unit thickness, when
unit difference of temperature is established between its faces [9, 24]. Thermal Resistance (R) for a
structure having plane parallel faces is equal to thickness (L) of the structure divided by (K) Eq. 1 .
Key Engineering Materials Vol. 632 3

Thermal conductance, C = K / L (1)

R = 1 / C = L / K (2)

For a composite material comprising several layers of conductivities K , K etc , and of thicknesses
1 2
L , L etc., the thermal resistance is :
1 2

R R + R + R + R + R + …….= (3)
T = 1 2 3 4 5
(cid:1)(cid:2) (cid:1)(cid:6) (cid:1)(cid:7) (cid:1)(cid:8) (cid:1)(cid:9) (cid:1)

(cid:3)(cid:2)+ (cid:3)(cid:6) +(cid:3)(cid:7)+(cid:3)(cid:8) + (cid:3)(cid:9) = ∑(cid:12)
Similarly, thermal transmission through unit area of a building unit divided by the temperature
difference between the air or other fluid on either side of the building unit in steady state conditions is
termed as Thermal Transmittance (U-value). For calculating the overall U- factor of typical opaque
wall construction, the U-factors of the typical wall and insulation shall be combined using the Eq. 4
[7, 25]:

, where, R + (4)
T =
(cid:14) (cid:14) (cid:14) (cid:1)(cid:2) (cid:1)(cid:6) (cid:1)(cid:7) (cid:1)(cid:8)

U = (cid:15)(cid:16) (cid:17)(cid:18) +(cid:17)(cid:19) +(cid:3)(cid:2) + (cid:3)(cid:6)+(cid:3)(cid:7) +(cid:3)(cid:8)
U = 1/ (1/h + L / K + 1/ h ) (5)
i i i o
(cid:20)
Where, R is t∑h(cid:21)e(cid:22) t(cid:14)o tal Resistance of the materials, h (19.86 W/(m2 K) and h (9.36 W/(m2 K) are the
T o i
outside and inside film heat transfer coefficients, L and K are thicknesses and thermal
i i
conductivities of material layers.

For calculating the overall U- factor of typical roof construction, the factors from the typical roof
construction type and effective U- factor for insulation have been combined according to the Eq. 6
(22 -23):

U = 1 / 1/U +U (6)
Total Roof Typical Roof Typical Insulation

Where,
U = Total U- factor of the roof with insulation
Total Roof
U = U - factor of the roof
Typical Roof
U = U - factor of the effective insulation
Typical Insulation

Similalry for calculating the overall U- factor of typical wall construction, the U-factors from the
typical wall construction type and for insulation are combined according to Eq. 7 (22 -23):

U = 1 / 1/U +U (7)
Total Wall Typical Wall Typical Insulation .

Where,
U = Total U- factor of the wall with insulation
Total Wall
U = U - factor of the wall
Typical Wall
U = U - factor of the effective insulation
Typical Insulation

Mandatory Wall and Roof Assembly U – factor and R- value Requirements
The Energy Conservation Building Code and National Building Code, Part 11 Approach to
Sustainability, 2014 of India defined the opaque wall and roof assembly U-factor and insulation
R-value requirements and to comply with either the maximum assembly U-factor or the minimum
R-value for the insulation alone as shown in Table 1 [22, 23]. But the way to achieve these values is
left to the designers. Hence, an attempt is made to accomplish this research gap.
4 Materials and Technologies for Green Construction
Table 1. Roofs and Opaque Wall Assembly U-factor and Insulation R-value Requirements
recommended by NBC

Climatic zones 24-Hour use buildings Daytime use buildings
(Hospitals, Hotels, Call Centers etc.) (Other Building Types)
Composite, Maximum Minimum Maximum Minimum
Hot & Dry and U - factor of the R – value of U - factor of the R - value of
Warm & Humid o v e r a l l assembly i n s u l a t i o n a l o n e o v e rall assembly insulation alone
(W/m2-°C) (m2-°C/W) (W/ m2-°C) (m2-°C/W)
Roof Assembly 0.261 3.50 0.409 2.10
Wall Assembly 0.440 2.10 0.440 2.10

Measurement of Thermal Conductivity of Materials
Thermal conductivity of insulating materials is measured by Automatic Guarded Hot - Plate
Apparatus available at CSIR- CBRI as shown in Fig.1. The apparatus works as per IS: 3346 principle
[24]. Density of each sample is determined before putting the sample in the test setup. Surface
temperature on both sides of the sample is measured by fixing Cu-constantan thermocouple on the
surfaces of the materials with the help of data logger. The voltage and current (power) is recorded by
Voltmeter and Ampere meter, when steady state temperature is achieved. The thermal conductivity is
determined by Eq. 8:

K= V x I x d / (2 x A (T -T )) (8)
H C

where, V, voltage in volt; I, current in ampere; d, thickness of the sample in millimeter; T and T ,
H C
temperatures of hot and cold plates respectively. The measured density and thermal conductivity
values of various insulating materials are given in Table 2.

The following types of walls, roofs and thermal insulating materials have been considered for
carrying out detailed analysis and computations of U-factor for walling and roofing assemblies.
These represent most of the materials used in the buildings:

Fig. 1 Guarded Hot - Plate Apparatus
Table 2. Thermal Conductivity of various insulation and other materials
Name of the Insulation Materials Density (Kg/m3) Thermal Conductivity (W/mK)
Expanded Polystyrene (EPS) 16.0 0.0380
Expanded Polystyrene (EPS) 24.0 0.0350
Polyurethane Foam (PUF)
32.0 0.0248
Fiber Glass (FG) 24.0 0.0360