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
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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
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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) ]