FABRICATE AND INVESTIGATE THE PERFORMANCE OF THE FLOW-THROUGH SOLAR EVACUATED TUBE USING WATER-BASED NANOFLUIDS

NORAZREEN BINTI SAMSURI

Thesis submitted in fulfilment of the requirements for the award of the degree of

Bachelor of Mechanical Engineering

Faculty of Mechanical Engineering UNIVERSITI MALAYSIA PAHANG

JUNE 2012

vi

ABSTRACT

Experiments are undertaken to determine the efficiency of Evacuated Tube Collector (ETC) using water based Titanium Oxide (Ti02) nanofluid at Pekan campus (3˚30’ N, 103˚ 25’ E) Faculty of Mechanical Engineering, University Malaysia Pahang for conversion of solar thermal energy. These projects are carried out to fabricate the bracket for Evacuated Tube Collector (ETC), to determine the best parameter and to compare the efficiency of water and Ti02. Malaysia lies in the equatorial zone with an average daily solar insolation of more than 900W/m2 and can reach a maximum of 1200 W/m2 for most of the year. Nanofluids are liquids in which nanosize particles of metal or their oxides are dispersed in a base liquid such as water. It results in higher values of thermal conductivity compared to the base fluid. The increase in thermal conductivity with temperature is advantageous for applications in collectors, as the solar insolation varies throughout the day, with a minimum in the morning reaching a maximum at about 2pm and reducing thereafter. The fabrication of bracket was done by using two hydraulic car jacks. The best parameter for ETC is verified by flow rate for water is 2.7L/min and the tilt angle throughout the year is 8.20. The increment by temperature different in ETC is 23.46% maximum with 0.3vt% for 30-50nm size Ti02 nanoparticles dispersed in water, compared to the system working with water. However, the efficiency of solar ETC increased with increment in concentration from 0.3vt% and distilled water is 25.89% when the flow rate is fixed at 2.7 LPM. Thus, the nanofluids is capable to absorb solar thermal energy at all available solar insolations in the present experiment.

ABSTRAK

Eksperimen yang dijalankan untuk menentukan kecekapan pemungut tiub yang dipindahkan (ETC) dengan menggunakan air berdasarkan Titanium Oksida (Ti02) nanofluid di Pekan kampus (3 ˚ 30 'N, 103 ˚ 25' E) Fakulti Kejuruteraan Mekanikal, Universiti Malaysia Pahang untuk penukarantenaga terma suria. Projek-projek ini dijalankan untuk memalsukan kurungan untuk pemungut tiub dipindahkan (ETC), untuk menentukan parameter yang terbaik dan untuk membandingkan kecekapan air dan Ti02. Malaysia terletak di zon khatulistiwa dengan purata harian sinaran matahari lebih daripada 900W/m2 dan boleh mencapai maksimum sebanyak 1200 W/m2 bagi kebanyakan tahun. Nanofluids adalah cecair di mana partikel saiz nano oksida logam atau mereka yang disebarkan dalam cecair asas seperti air. Ia menyebabkan nilai-nilai yang lebih tinggi kekonduksian terma berbanding dengan bendalir asas. Peningkatan dalam kekonduksian terma dengan suhu berfaedah bagi permohonan dalam pengumpul, sebagai sinaran matahari berubah-ubah sepanjang hari, dengan sekurang-kurangnya pada waktu pagi mencapai maksimum pada kira-kira 2 petang dan penurunan selepas itu. Fabrikasi pendakap telah dilakukan dengan menggunakan dua bicu hidraulik kereta. Parameter terbaik untuk ETC disahkan oleh kadar aliran air adalah 2.7L/min dan sudut kecondongan sepanjang tahun adalah 8.20. Kenaikan perbezaan suhu dalam ETC adalah maksimum 23.46% dengan 0.3vt% untuk 30-50nm saiz Ti02 nanopartikel yang berselerak di dalam air, berbanding dengan sistem yang bekerja dengan air. Walau bagaimanapun, kecekapan ETC meningkat dengan kenaikan tumpuan dari 0.3vt% dan air suling adalah 25.89% apabila kadar aliran ditetapkan pada kadar 2.7L/min. Oleh itu, nanofluids mampu untuk menyerap tenaga haba suria di semua sinaran matahari dalam eksperimen ini.

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TABLE OF CONTENTS

Page

TITLE PAGE i

SUPERVISOR’S DECLARATION ii

STUDENT’S DECLARATION iii

DEDICATION iv

ACKNOWLEDGEMENTS v

ABSTRACT vi

ABSTRAK vii

TABLE OF CONTENTS viii

LIST OF FIGURES xi

LIST OF TABLES xii

LIST OF SYMBOLS xiv

LIST OF ABBREVIATIONS xv

CHAPTER 1 INTRODUCTION

1.1 Background 1

1.2 Problem Statement 2

1.3 Objectives 3

1.4 Scope of Project 3

CHAPTER 2 LITERATURE REVIEW

2.1 Introduction 4

2.2 Renewable Energy 4

2.2.1 World Energy Scenario 5 2.2.2 Energy Resources in Malaysia 7 2.2.2.1 Generation Fuel Options 7 2.2.2.2 Oil 8 2.2.2.3 Natural Gas 8 2.2.2.4 Coal 8 2.2.2.5 Hydroelectricity 9 2.2.2.6 Renewable Energy 9

2.3 Solar Energy 9

2.4 Evacuated Tube Solar Collector (ETSC) 13

2.4.1 Evacuated Tube and Tilt Angle 17 2.4.2 Overall Heat Loss Coefficient of ETSC 18

ix

2.4.3 The ETSC Efficiency 18

2.5 Solar Water Heater 19

2.6 Nanofluid 20

2.6.1 Introduction 20 2.6.2 History 21 2.6.3 Preparation of Nanofluid 23 2.6.3.1 Two-Step Method 24 2.6.3.2 One-Step Method 25

2.7 Conclusion 26

CHAPTER 3 METHODOLOGY

3.1 Introduction 27

3.2 Flow Through ETSC Panel (SEIDO 2-16) 29

3.2.1 Customization and Convenience 30 3.2.2 Top Performance and Versatility 30

3.3 Design and Fabrication of Test Rig 31

3.4 Preparation of Nanofluids 33

3.4.1 The Step for Preparing Nanofluids in Two Step Method

33

3.4.2 The Step for Dilution Process 35

3.5 Full Fabrication and Installation 36

3.6 Equipments 37

3.6.1 Weather Station 37 3.6.2 Temperature Recorder/ Thermocouple

Monitor 38

3.6.3 Electronic Sensitive Balance 39 3.6.4 Magnetic Hotplate Stirrer 40 3.6.5 Ultrasonic Homogenizer 41 3.6.6 Digital Overhead Stirrer 42 3.6.7 KD2 Pro 43 3.6.8 Daystar Solar Meter 44 CHAPTER 4 RESULT AND DISCUSSION

4.1 Selecting The Best Flow Rate 45

4.1.1 Selection of Flow Rate 45

4.2 Selecting Collector Tilt Angle 46

4.2.1 Value Determination for n 46 4.2.2 Comparison between Prediction and Actual

Annual Solar Insolation for Tilt Angle 47

4.2.3 Sample Calculation for Tilt Angle 48

x

4.3 Average Daily Solar Insolation 52

4.3.1 Effects of Sunny and Cloudy Day to Solar Insolation for FKM

52

4.3.2 Comparison between Global Radiation and Global Tilt Radiation

54

4.3.3 Effect of Temperature Different due to Solar Insolation

55

4.4 Temperature Different Evaluation 57

4.4.1 Temperature Evaluation of Nanofluids and Distilled Water on ETSC

57

4.4.2 Reducing Volume Concentration to 0.2% of Titanium Oxide and Increase The Flow Rate to 3ℓ/min

58

4.5 Efficiency of Overall ETSC 59

4.5.1 Sample Calculation for Efficiency of Distilled Water and Nanofluid Alumina

59

4.5.1.1 Sample Calculation for The Instantaneous Collector Efficiency of Distilled Water

59

4.5.1.2 Sample Calculation for The Instantaneous Collector Efficiency of Nanofluid 0.3% Titania

59

4.5.2 Efficiency of Overall ETSC for Distilled Water on 13 April 2012

61

4.5.3 Efficiency of Overall ETSC for Nanofluids Titania 0.3% versus Time on 18 April 2012

62

4.5.4 Efficiency of Overall ETSC for Nanofluids Titania 0.2% versus Time on 3 May 2012

63

4.5.5 Efficiency of Overall ETSC for Distilled Water and 0.3% Titania due to the solar insolation

64

CHAPTER 5

5.1 Conclusion 65

5.2 Recommendation 66

REFERENCES 67

APPENDICES 69

xi

LIST OF FIGURES

Figure No. Title Page 2.1 World primary energy consumption 2011 5 2.2 World renewable energy resources 2009-2010 6 2.3 List of energy resources 6 2.4 Properties of solar radiation 10 2.5 Irradiation under different weather conditions 11 2.6 Array orientation can be described using azimuth or tilt

angles for installation solar system 11

2.7 Function in solar thermal energy 12 2.8 Construction of evacuated tube solar collector 13 2.9 Heat pipe evacuated tube solar collector 14 2.10 Flow through evacuated tube solar collector 15 2.11 Schematic diagram of flow through evacuated tube solar

collector 15

2.12 Breakage or leakage of evacuated tube solar collector 16 2.13 Types of system of collector 16 2.14 Photographic view of nanoparticle 23 2.15 SEM images of nanoparticles on 1μmscales 24 2.16 SEM images of nanoparticles on 500nm scales 24 3.1 Flow chart of simulation 28 3.2 SEIDO 2-16 29 3.3 Flow of the cold and hot liquid inside the SEIDO 2 30 3.4 Overall evacuated tube solar collector installation 31 3.5 Sketch for designing panel bracket 32 3.6 Fabrication of solar panel bracket 32

xii

3.7 Nanofluids with high concentration by weight percent 35 3.8 Low concentration of nanofluids by volume percent 35 3.9 The schematic of the experiment 36 3.10 The flow diagram of the experiment 37 3.11 Weather Station 38 3.12 Thermocouple monitor 39 3.13 Electronic Sensitive Balance 39 3.14 Magnetic hotplate stirrer 40 3.15 Ultrasonic homogenizer 41 3.16 Digital overhead Stirrer 42 3.17 KD2 Pro 43 3.18 Daystar solar meter 44 4.1 Comparison between various types of flow rate and

temperature different 45

4.2 Example Average Solar Insolation collector against Time

(23rd February 2012) for clear day 52

4.3 Example Average Solar Insolation collector against Time

(27th February 2012) for cloudy and rainy day 53

4.4 Example Effect on Direct Solar Insolation and Collector

Solar Insolation against Time (16th March 2012) 54

4.5 Example Effect on Temperature against Time (16th March

2012) 55

4.6 Example Effect on Temperature Different and Solar

Insolation Collector against Time (16th March 2012) 56

4.7 Comparison between distilled water and nanofluids 0.3%

volume concentration of Titania / Titanium Oxide (Ti02) 57

4.8 Comparison between distill water, 0.3% concentration and

0.2% concentration of Titania 58

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4.9 Efficiency of distilled water against time on 13th April 2012

61

4.10 Graph efficiency of nanofluids Titania (Ti02) 0.3vt%

against time 62

4.11 Graph efficiency of nanofluids Ti02 0.2vt% versus time 63 4.12 Graph efficiency of distilled water and 0.3vt% Titania

against solar insolation 64

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LIST OF TABLES

Table No. Title Page 2.1 Thermal conductivities of various solids and liquids 21 3.1 Physical properties of nano materials 34 3.2 Specifications of hotplate stirrer 40 3.3 Specifications for ultrasonic homogenizer 41 3.4 Specifications for digital overhead stirrer 42 3.5 Specifications for KD2 Pro 43 3.6 Specifications for daystar solar meter 44 4.1 Specific dates on which the day value is equal to monthly

average value 46

4.2 n value determination 46 4.3 Solar energy parameters from NASA surface meteorology

and solar energy 47

4.4 Prediction of radiation data by calculation 48 4.5 Calculation for optimum tilt angle for evacuated tube solar

collector 51

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LIST OF SYMBOLS

η Efficiency of the system 𝜂𝑜 Correlation Coefficient 𝑇𝑎 Ambient temperature, oC 𝑇𝑚 Mean temperature, oC 𝑇𝑜𝑢𝑡 Outlet temperature, oC 𝑇𝑖𝑛 Inlet temperature,oC 𝐺𝑇 Global solar radiation, W/m2 𝐴𝑐 Surface area of collector, m2 �̇� Mass flow rate, kg/s 𝑄𝑢 Heat rate, W 𝐶𝑝,𝑤 Specific heat of water at constant pressure, J/kg.oC 𝜌𝑤 Density of water, kg/m3

𝜌𝑝 Density of nanoparticle, kg/m3 𝜙 Volume concentration of nanoparticle in volume percent 𝜑 Volume concentration of nanoparticle in weight percent 𝜌𝑤 Density of water, kg/m3 𝑚𝑝 Mass of nanoparticle, g 𝑚𝑤 Mass of water,g n Leap year/ Non leap year + Day β Angle made by the plane surface with the horizontal Isc Solar constant δ Declination angle ωst Hour angle

xv

NMAX Monthly average of maximum possible sunshine hours per day, in

hours

oH Monthly average of daily extraterrestrial radiation on a horizontal surface, kJ/m2.day

gH Monthly average of daily global radiation on a horizontal surface,

kJ/m2.day a, b Regression coefficients which vary from site to site

dH Monthly diffuse radiation, kJ/m2.day

bH Monthly beam radiation, kJ/m2.day βopt Optimum angle

Ic Solar radiation at collector, W/m2

nfCp Nanofluids specific heat energy, J/kg.K

pCp Nanoparticle specific heat energy, J/kg.K

LIST OF ABBREVIATIONS

ETSC Evacuated Tube Solar Collector SRCC Solar Rating and Certification Corporation UMP Universiti Malaysia Pahang RE Renewable Energy TNB Tenaga Nasional Berhad IPP Independent Power Producers ETC Evacuated Tube Collector SWH Solar Water Heater Al2O3 Aluminium Oxide / Alumina EG Ethylene Glycol EO Engine Oil CuO Cuprum Oxide SiO2 Silicon Oxide / Silica SEM Scanning Electron Microscope TiO2 Titanium Oxide / Titania PV Photovoltaic FKM Fakulti Kejuruteraan Mekanikal

CHAPTER 1

INTRODUCTION

1.1 BACKGROUND

The greatest potential of all sources of renewable energy is solar energy

especially when other sources in the country have depleted. There are so many methods

that have introduced to increase the efficiency of the solar water heater. Solar Energy

collectors are special kind of heat exchangers that transform solar radiation energy to

internal energy of the transport medium. The principle involve in collecting solar energy

is rather simple depending on the receiving surfaces which are able to absorb as much

as possible of the incoming solar flux. The ability to retain heat is a condition and

transferred through tubes by working fluids. There are many types of solar collector

such as flat plate, evacuated tube and heat pipe. In this project will concern about the

flow through evacuated tube solar collector.

However, the novel approaches to introduce the nanofluids in solar water heater

instead of conventional heat transfer fluids. The poor heat transfer properties of these

conventional fluids compared to most solids are the primary obstacles to high

compactness and effectiveness in the system. The essential initiative is to seek the solid

particles having thermal conductivity of several hundred times higher than those of

conventional fluids. An innovative idea is to suspend ultrafine solid particles in the fluid

for improving the thermal conductivity of the fluid.

2

1.2 PROBLEM STATEMENT

Nowadays, some building in Malaysia are using on solar water heater system,

and the main reason is to energy saving in hot water technologies. The current problems

faced by solar water heater are;

1. The material cost for build solar technology is the biggest problem. The material

such as evacuated tube solar collectors is still very expensive. Therefore, this

project will reduce the payback period of building solar collector.

2. Another major problem to have a solar energy as renewable energy is that every

location on Earth does have the same direct sunlight. Most of the areas in this

world only can used a low-power solar energy because of cloud cover that limits

the availability of solar energy.

3. Certain types of solar water heating system cannot function when on cloudy time

and need a backup water heating system to ensure the hot water available all the

times. This system cannot be used in freezing temperatures in the country that

have winter season. However, Malaysia can prevent this problem because of the

weather in Malaysia is good enough to make the solar collector the best

efficient.

4. There are two methods to prepare the nanofluids. However, many of researchers

are still in research to find the best way of preparing the nanofluids. Many of

them are working with the problem on stability of nanofluids that have the

sedimentation in the nanofluids.

3

1.3 OBJECTIVES

The objectives are:

1. To fabricate the bracket for Evacuated Tube Solar Collector (ETSC) and the

systems.

2. To develop an efficient water-based nanofluid solar collector by optimizing the

flow rate and collector tilt angle that applicable to Pekan.

3. To compare the efficiency of water and water-based nanofluid flow through

evacuated tube solar collector.

1.4 SCOPE OF PROJECT

The scopes are:

1. Equipments:

a. Flow Through Evacuated Tube Solar Collector

Model: SEIDO 2-16

Feature: One of the highest performing Solar Rating and Certification

Corporation (SRCC) rated thermal collectors. The collector can be

oriented in any manner. The absorption coefficient is more than 92% by

using Aluminium Nitride coating.

b. The solar flow through evacuated tube data was collected manually with

the interval 15minutes.

2. The location of the experiment will be in Universiti Malaysia Pahang (UMP),

Pekan.

3. Calculation will be instantaneous efficiency.

CHAPTER 2

LITERATURE REVIEW

2.1 INTRODUCTION

This literature review explores about four major scopes in this report which are

renewable energy, solar energy, evacuated tube solar collector and nanofluids. The

literature review provides a background to the study being proposed. The background

may consider previous findings, rational of the relevant study, methodology or research

methods, and theoretical background. Most of the literature reviews have been extracted

from journals, books and web site. This is important because we can avoid the same

mistakes done by the previous study. However, with these literature reviews, the project

can be run smoothly.

2.2 RENEWABLE ENERGY

The word energy is derived from the Greek en (in) and ergon (work). There are

many forms of energy which are heat, work, chemical energy in forms of fuels or

batteries, kinetic energy which in moving substances, electrical energy, gravitational

energy and potential energy by virtue of its elevation. Energy can divide into two major

of energy. There are alternative energy that refers to any source of usable energy

intended to replace fuel sources without the undesired consequences of the replaced

fuels; and renewable energy that refers to energy which comes from natural resources

such as sunlight, wind, rain, tides, and geothermal heat, which is naturally replenished.

5

2.2.1 World Energy Scenario

World Primary Energy Consumption 2011

Figure 2.1: World’s energy scenario

[Source: (Bredenberg May 7th, 2012) ]

Mostly, world primary energy consumption is based on energy that

already has but mainly of this energy can be depleted. Renewable energy

contributes 14% energy to the world. Therefore, we should increase the usage of

renewable energy. The bad effects on environment caused by the production and

consumption of energy have resulted in harsh environmental impacts across the

globe. The supply of energy is expected to remain as much as necessary in

coming years. However, imbalance of energy consumption is common around

the world. Energy consumption is high in most developed countries. On the

other hand, the developing countries need to consume more energy to ensure

economic growth. The economic development of many countries is caught up

due to “energy poverty”.(EconomyWatch 30 April 2010)

The major sources of energy in the world are oil, coal, natural gas, hydro

energy, nuclear energy, renewable combustible wastes and other energy sources.

Combustible wastes include animal products, biomass and industrial wastes.

Renewable energy will be more concentrate in this project because to helps and

decrease the usage of available energy.

29%

27%

23%

14%

7%

Petroleum

Coal

Natural Gas

Renewables and Other Sources

Nuclear

6

Biogas 12%

Hydro 20%

Wind 41%

Biomass 20%

Solar 7%

World Renewable Energy Resources 2009-2010

Figure 2.2: World’s energy scenario in renewable energy sources

[Source: (Gabor 2011) ]

Figure 2.2 shows the renewable energy scenario in this world.

Traditional Biomass gives the big amount of energy resources to provide energy

to peoples. Tidal energy is the lowest application in renewable energy. There are

many initiatives to educate the peoples in this world about the important of

renewable energy.

Figure 2.3: Energy Resources

[Source: (Frank Kreith 1942) ]

7

The energy resources are divided into two major parts which are non-

renewable and renewable energy. Under the renewable energy, there are many

types of energy that provide energy to our needs. However, this project is about

the solar energy.

Renewable energy can be particularly suitable for developing countries.

In rural and remote areas, transmission and distribution of energy generated

from fossil fuels can be difficult and expensive. Producing renewable energy

locally can offer a viable alternative. Renewable energy projects in many

developing countries have demonstrated that renewable energy can directly

contribute to poverty elimination by providing the energy needed for creating

businesses and employment. Renewable energy technologies can also make

indirect contributions to elimination poverty by providing energy for cooking,

space heating, and lighting. Renewable energy can also contribute to education,

by providing electricity to schools.

2.2.2 Energy Resources in Malaysia

2.2.2.1 Generation Fuel Options

The New Five-Fuel Diversification Strategy replaces the Four-Fuel

Diversification Strategy, in which the fifth fuel under the New Strategy is non-

hydro renewable energy (RE) alongside the existing four fuels utilised for power

generation, namely, oil, gas, coal and hydro. The Four-Fuel Strategy and

subsequently the New Five-Fuel Strategy has been successful in bringing down

oil consumption for power generation from more than 80% in the 1980's to

about 32% in 1998 and further down to about 4% in 2000. The Government is

also looking into efficient energy utilisation and consumption through the

National Energy Efficiency Strategy. There are therefore no firm plans at

present for the introduction of nuclear power generation, although Tenaga

Nasional Berhad (TNB) maintains an interest in nuclear power technology

through a continuing programme of technical and manpower training. TNB has

the largest generation capacity of over 7,500 MW that accounts for over 62% of

the total power generation of Peninsular Malaysia.

8

2.2.2.2 Oil

In the early eighties, oil-fired generation contributes to a substantial

proportion of TNB's output and operating costs were significantly affected by

excursions in oil prices since late 1973. Despite current low prices of fuel oil,

oil-fired generating plants are not considered to be strongly competitive options

for long term planning purposes, in view of the uncertainties of future prices,

and other available alternatives. In TNB, oil requirement has reduced over the

years.

2.2.2.3 Natural Gas

Natural gas has become an important fuel for gas turbines and combined-

cycle plant developments, both for TNB and IPPs. The Phase II of the Peninsular

Gas Utilisation Pipeline Project has made available natural gas to the West Coast

and South of Peninsular Malaysia in the late 1991.

With the completion of the gas pipeline project and the advent of

Independent Power Producers (IPP) in 1994, gas utilisation in power generation

has increased tremendously. To-date, gas contributed to about 76% of the total

generation capacity mix.

2.2.2.4 Coal

Coal is also commercially available from foreign sources and this fuel is

an option for our power generation development studies. Current indications are

that imported coal will be a competitive fuel source for electric power generation

in Malaysia. The third phase Port Klang Power Station, which was scheduled to

be commissioned in 2001, comprises two 500 MW coal-fired units capable of

burning coal or gas or oil. In addition, the Janamanjung Power Station which is a

2,100 MW coal-fired plant is expected to come online in year 2003.

More coal-fired plants (including IPPs) have been proposed in the years beyond

2000 for security of power supply and to conform to the diversification of fuel

usage in power sector as required by the national fuel policy. Currently coal-

fired generation constitutes about 5% of the total generation capacity mix.

9

2.2.2.5 Hydroelectricity

It is estimated that the indicative hydro potential in Peninsular Malaysia

totals some 16 TWh/year. Nine major hydro stations with a capacity of 1,874

MW are currently in service. This total capacity includes the recently

commissioned Pergau Hydroelectric Station (in 1997) which contributes a total

peaking capacity of 600MW. Three other hydroelectric projects have been

identified and under planning stage namely, Ulu Terengganu (300MW),

upgrading of Kenyir Hydro station (300MW) and Ulu Jelai's mixed pumped

storage (1,000MW- 1,200MW) with 300MW conventional hydro scheme.

2.2.2.6 Renewable Energy

Renewable energy (RE) has been identified and finalised by the

Government as the fifth fuel under the New Five-Fuel Diversification Strategy.

The RE focus would be on biomass, especially from palm oil and wood wastes.

The target of contribution towards the total electricity generation mix from RE is

5% by 2005 and 10% by 2010, after which this ratio could be maintained

thereafter.

2.3 SOLAR ENERGY

An incredible supply of solar energy has received by the earth. An average star,

the sun is a fusion reactor that has been burning over 4 billion years. In fact, “The

amount of solar radiation striking the earth over a three-day period is equivalent to the

energy stored in all fossil energy sources.” Sun provides energy in one minute to supply

the world’s energy needs for one year. In one day, sun can provides more energy than

our current population would consume in 27 years. It means, the sun can deliver 7000

times more energy to the Earth’s surface. Earth receives approximately 170 million GW

of power from the sun, which is a relatively tiny fraction of the sun’s total output, but is

millions of times greater than the maximum power demand of Earth’s entire population.

The Earth distance from the sun is 149,596,000 km, therefore, the solar flux relatively

small. About 1369 watts per square meter (W/m2) is the intensity of the solar radiation

that reaches us and this values also known as Solar Constant. To put it another way,

10

solar energy captured by the Earth over a period of 1000 years is equal to the energy

produced by the Sun in just only 14 seconds.

Figure 2.4: Properties of Solar Radiation

[Source: (D. Yogi Goswami 2000) ]

The information on sunshine hour, solar radiation intensity and daily variation of

global solar radiation are one of the important aspects to design a suitable solar system

for a particular application such as photovoltaic water pumping system, solar thermal

and drying system. In tropical countries like Malaysia, the cloud pattern can be highly

variable due to high humidity and unpredictable weather, especially during the monsoon

seasons. Mainland Malaysia is a peninsula lying between latitudes 1.30 and 6.600N, and

longitudes 99.50 and 103.300E. As in many places at Malaysia is mainly influenced by

the system of the Asian monsoons. (Mohd Yusof Hj. Othman 1992)

Some observers has observed at Malaysia that instantaneous solar radiation

intensity sometimes rises higher than solar constant, even reaching 1.4 kW/m2 which is

the saturation point of the recording system. For such a clear day, the maximum

instantaneous solar intensity was 971 W/m2 and the amount of solar energy received

during the whole day was 6.957kWhr/m2. For the whole day, about 12hours Malaysia

will receive the amount of solar energy which is from 7 a.m. until 7 p.m. The

comparison of lower value than desert area is because the atmosphere in Malaysia is

denser than desert due to the higher humidity. Besides that, for fully cloudy day, the

maximum solar intensity received was 121.4 W/m2 and for the whole day was

0.5kWhr/m2. For partly cloudy day, the maximum solar intensity can get around 1142.9

W/m2 and total solar radiation was 4.43kWhr/m2.(Mohd Yusof Hj. Othman 1992)

11

Figure 2.5: Irradiation under different weather conditions

[Source: (SP Sukhatme 2009)]

Furthermore, the global solar radiation pattern with instantaneous intensity

higher than solar constant was record 1400 W/m2 which the maximum intensity that

recorded and the total amount solar radiation on that day can achieve 4.16kWhr/m2. The

difference in units by using W/m2 and kWhr/m2 are for W/m2, are taking from the

reading. However, for kWhr/m2 is the total of solar radiation times by the sun received

for the whole day. Other than that, when it’s rainy in the afternoon, the maximum

instantaneous solar intensity was 957 W/m2 and total solar radiation received for the day

was 3.00kWhr/m2.(Mohd Yusof Hj. Othman 1992). Due to this consideration, the

specifications and components solar system can be determine for installation in

Malaysia and similar locations.

Figure 2.6: Array orientation can be described using azimuth or tilt angles for installation solar system

[Source: (John A. Duffie 2006) ]