COMPARATIVE STUDY OF THERMAL PROPERTIES OF SOME COMMON ROOFING MATERIALS IN NIGERIA

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COMPARATIVE STUDY OF THERMAL PROPERTIES OF SOME COMMON ROOFING MATERIALS IN NIGERIA

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Author

Presented To

Department of Physics

56 Pages 9,911 Words 2,701 Views PDF Format No. of Chapters: 1 to 5 Chapters

ABSTRACT

Thermal properties refer to characteristics of a material defining the substance and related to

temperature dependent. The most important thing in building design is the protection of people who

live and work within the environment. The research work identified some common roofing materials

used for building design in Nigeria.. The samples include aluminium (coated), Zinc and stone coated.

The investigation was done using Ohm‟s law and Frankz Weidman principle. The thermal properties

investigated were thermal conductivity, thermal absorptivity, thermal diffusivity, thermal resistivity

and specific heat capacity. with the view of establishing their suitability as roofing materials in

building design in Nigeria based on climate and weather condition of particular location. the results

show that zinc has the highest thermal conductivity

,thermal absorptivity

and specific heat capacity

and also the lowest thermal diffusivity

andthermal resistivity while stone coated material has the least thermal

conductivity

, absorptivity

,and specific heat capacity

and also the highest rate of thermal diffusivity

, and thermal resistivity

Aluminum coated is within the range of both sample, with thermal conductivity

thermal absorptivity

, thermal diffusivity

, thermal resistivity

and specific heat capacity

.Thus stone coated material may be

recommended for roofing of building where the temperature is high and zinc may be recommended

for roofing of buildings where temperature is low. For normal temperature range, Aluminium

material may be recommended.

TABLE OF CONTENTS

TITLE PAGE i

DECLARATION ii

CERTIFICATION iii

DEDICATION iv

ACKNOWLEDGEMENT v

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xi

ABSTRACT xii

CHAPTER ONE: INTRODUCTION

11 Background of the study 1

12 Aim and objectives 2

13 Significance of the study 3

14 Scope and limitation of the study 3

15 Definition of terms 3

CHAPTER TWO: REVIEW OF RELATED LITERATURE

21 Thermal Properties of Roofing Material 5

22 Thermal Conductivity 5

23 Method of Measuring Thermal Conductivity 5

231 Steady‐State Method 5

232 Axial Flow Methods 6

233 Guarded Hot Pla bte Method 6

234 Direct Heating Method 7

235 Comparative Method 7

236 Heat‐Flow Meters Method 8

237 System Design Method 8

238 Advantages of the Steady‐State Methods to Other Methods 8

239 Disadvantages of the Steady‐State Methods to Other Methods 9

2310 Determination of Thermal Conductivity in Steady State 9

2311 Non steady state or Transient Method 10

2312 Laser Flash Method 10

2313 Hot‐Disk Method 10

24 Thermal Resistivity (R) 12

25 Thermal Conductance(C) 12

26 Thermal Diffusivity 12

27 Thermal Absorptivity 13

28 Specific Heat Capacity 13

29 Relationship between Thermal Conductivity Thermal Diffusivity, Density and

Specific Heat Capacity 13

210 Heat Transfer 15

2101 Conduction 16

2 102 Convection 16

2103 Radiation 16

211 Heat Transfer through A Roof 17

212 Thermal Radiation 18

213 Solar Radiation 18

214 Solar Absorption 19

215 Roof Colour 20

216 Review of Previous Work 21

CHAPTER THREE: MATERIALS AND METHODS

31 Materials 23

32 Sample preparation 24

33 Methods 24

34 Circuit Diagram 26

35 Experimental Procedure for Electrical Conductivity 27

36 Experimental Procedure for Specific Heat Capacity 28

37 Experimental Procedure for Density 28

CHAPTER FOUR: RESULT AND DISCUSSION

41 Result of sample dimensions and mass measurement 29

42 Computation of Cross Sectional Area of the Sample 29

43 Density of Each Sample 30

44 Experimental Results of Resistance, Electrical Resistivity and

Electrical Conductivity 30

45 Results of thermal properties of the sample 32

46 Graphical Analysis of Result 34

CHAPTER FIVE: SUMMARY CONCLUSION AND RECOMMENDATION

51 Summary 39

52 Conclusion 40

53 Recommendation 40

References

LIST OF TABLES

TABLE PAGE

41 Sample dimension and Mass 29

42 Cross sectional area of each sample 30

43 Density of each sample 30

44 Experimental results of resistance, electrical resistivity and

electrical conductivity 32

45 Statistics of thermal properties of different roofing samples 33

CHAPTER ONE

INTRODUCTION

11 BACKGROUND OF THE STUDY

Provision of housing among other social amenities occupies a strategic position in most development

plans for developing Nations such as Nigeria (Chukwucha, and Owate, 2002) One of the

fundamental requirements of buildings is the protection of the people who live and work within them

from hash weather Thus, objective of environmental building design is the creation of a comfortable

yet efficient internal environment (Camilleri, 2000)

The design of the building envelope is crucial towards attaining an optimal configuration, which

responds effectively to environmental changes in order to reduce their impact The understanding of

energy related characteristics and the evaluation of the relevant properties of the building envelope is

an integral part of every environmental assessment Solar energy affects significantly, the interior

environment and the energy requirements of buildings (Lattimer & Ouelletes 2006)

However, one way to reduce the heat flux is the use of radiant barriers which reduce the heat flux

through radiation Most building materials particularly, roofing materials are good conductor of heat

Materials like metal and tile are commonly used in the form of sheet metal for roofing in building

construction

The knowledge of thermal properties of different roofing material is very important in the choice of

the type of material to be used in the construction of a self- cooling or passively cooled building

design (Etuk, et al, 2008 & Michael, et al, 2008)

However, roofing systems used in the formal and residential sector are predominantly timber or

metal truss systems with tile or profiled steel roofing, generally these roofing systems will be

complimented with a plasterboard ceiling, regulations which require that these roof assemblies are

insulated

Therefore, thermal insulation is applied above the ceiling to achieve the thermal resistance

requirements The requisite thermal resistance can be achieved by adding additional layers of fibrous

loft insulation or with reflective foil layers to create air-spaces or by making use of thermally

insulating board products(Safintra roofing and steel South Africa, 2016)

In the recent observation, it has shown that roofing materials used in building design doesn‟t take

sufficient account of climate and environmental factors in the design, most especially with the

regards to the choice of roofing materials to be used These situations would increase the energy

consumption for heating and cooling in buildings and affects comfort, health and efficiency

Therefore, it is important to carry out adequate research on thermal properties of these roofing

materials

12 Aim and Objectives

The aim of this research is to measure and compare the thermal properties of some common roofing

materials in building design in Nigeria

The Objectives are;

i To identify common roofing material used for buildings in Nigeria

ii To measure and compare specific heat capacity of these materials

iii To measure and compare thermal conductivity as well as to evaluate thermal resistivity of

the materials

iv To measure and compare thermal diffusivity of material

v To measure and compare thermal absorptivity of material

13 Significance of the study

The result of this research would enable the builder in Nigeria, to choose the best roofing materials

for the residential and industries construction that will prevent any outbreak

14 Scope of the study

This research work focuses on identifying the common roofing material in Nigeria for building

design The thermal properties of these roofing materials will then be study comparatively by

measuring conductivity, resistivity, absorptivity, diffusivity and specific heat capacity of the roofing

material The measurement will be carry out in the laboratory for necessary computations, at the end

of the experiment the result will be show graphically

15 Definition of Terms

Temperature: is measure the degree of hotness or coldness expressed in terms of any several

arbitrary scales and indicating the direction in which energy will spontaneously flow, ie from higher

body to lower body Thermometer is an instrument use to measure the temperature of a system

Heat (Q): is the transfer of energy between two objects due to temperature differences Without

external agent doing work, heat will flow a hotter to a cooler object Two objects of different

temperature always interact Heat can be flow in three different ways from one object to another

through conduction, convection and radiation

Heat flux: is the rate of heat energy transfer through a given surface per unit time

Thermal properties: any characteristic of a material defining the substance and related to

temperature; eg thermal conductivity is said to be a thermal property, but electrical conductivity is

not

Weather: is the state of the atmosphere to the degree of hot or cold, wet or dry calm or stormy, clear

or cloudy Weather is driven by air pressure, temperature and moisture difference between one place

and another

56 Pages 9,911 Words 2,701 Views PDF Format No. of Chapters: 1 to 5 Chapters

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