ANALYSIS OF WIND LOADING ON SOLAR PANEL AT DIFFERENT

INCLINATION ANGLES IN MALACCA WEATHER CONDITION

NURUL YASMIN BINTI MOKHTAR

B041110202

BMCT

Email: nurulyasminmokhtar@gmail.com

Final Report Draft

Final Year Project II

Supervisor: DR. MOHD ZAID BIN AKOP

Faculty of Mechanical Engineering

Universiti Teknikal Malaysia Melaka

MAY 2015

i

SUPERVISOR DECLARATION

“I hereby declare that I have read this thesis and in my opinion this report is sufficient

in terms of scope and quality for the award of the degree of Bachelor of Mechanical

Engineering (Thermal- Fluids) with Honors”

Signature : _______________________

Supervisor : DR. MOHD ZAID BIN AKOP

Date :

ii

ANALYSIS OF WIND LOADING ON SOLAR PANEL AT DIFFERENT

INCLINATION ANGLES IN MALACCA WEATHER CONDITION

NURUL YASMIN BINTI MOKHTAR

This Report Is Submitted In Partial Fulfillment of Requirement For The Bachelor

Degree Of Mechanical Engineering (Thermal-Fluid) With Honors

Faculty of Mechanical Engineering

Universiti Teknikal Malaysia Melaka

(MAY 2015)

iii

DECLARATION

“I hereby declare that the work in this report is my own except for summaries and quotations which have been duly acknowledged”

Signature: ____________________

Author: NURUL YASMIN BINTI MOKHTAR

Date: 28 MAY 2014

iv

“Timothy Leroy Lincecum, for his pitching mechanic, the marvel of unorthodox engineering”

v

ACKNOWLEDGEMENT

Alhamdulillah and praise to Allah with His willingness, this Final Year Project

has successfully been done within acquired timeframe. I wish to express my deepest

gratitude to my supervisor, Dr. Mohd Zaid Bin Akop for his guidance, advices and

information throughout this project.

I am also grateful for the assistance of Mr.Razmi Bin Abd Razak for his

teaching and advices regarding the wind tunnel experiment and Dr. Cheng See Yuan for

his ideas on how to solve the simulation. I extend my thanks to my beloved husband,

my beautiful daughter, family for their support spiritually and economically, and friends

for their shared knowledge and time in completing this analysis.

vi

ABSTRACT

The field of renewable energy has been widely growing topic of fascination by

researchers, industrialist and the public alike. Solar technology is becoming increasingly

popular for the past few decades and Malacca has become a home for solar energy

harnessing where it houses 5MW solar farm owned by Kumpulan Melaka Berhad and a

key project for Malacca to become a green technology state by 2020. Like any other

structure, solar photovoltaic panels are subjected to wind loading and the effort to

minimize the structural damages due to high wind has become the main interest for

many. This study attempt to investigate the effect of wind loading on solar panel at

different inclination angles using two common method ; CFD and wind tunnel testing.

For computational fluid dynamics, Reynold Average Navier Stoke (RANS) equation of

k-ε turbulent closure modeling is use. The result obtain from the simulation will be

compare and validate with force measurement system in wind tunnel testing. The

images of velocity contour generated from simulation managed to reveal the flow

behavior such as flow separation, wake region and are compared with images captured

using smoke generator in the wind tunnel experiment.

vii

ABSTRAK

Bidang tenaga boleh dibaharui telah menjadi satu bidang yang menarik minat ramai

penyelidik akademik, pihak industri, dan termasuk orang awam. Sejak beberapa dekad,

teknologi solar telah menyaksikan peningkatan permintaan dan semakin mendapat

tempat di pasaran. Negeri Melaka sendiri merupakan negeri pertama mempunyai ladang

solarnya yang berkapasiti 5MW milik Kumpulan Melaka Berhad dan merupakan projek

ulung bagi Melaka yang bercita-cita untuk menjadi negeri berteknologi hijau menjelang

tahun 2020. Akan tetapi, seperti struktur lain panel solar juga tertakluk pada beban

angin dan langkah untuk mengurangkan kesan beban angin telah menjadi satu fokus

utama ramai pihak. Kajian ini bertujuan untuk mempelajari kesan beban angin pada

panel solar jika dikenakan pada sudut condong yang berlainan dengan menggunakan

dua kaedah iaitu simulasi CFD dan ujian terowong angin. Untuk CFD, persamaan

Reynold Average Navier Stoke (RANS) jenis k-ε akan digunakan dan hasil dapatannya

akan dibandingkan dengan hasil dapatan pengukuran daya daripada terowong

angin.Imej kontur hadlaju yang terhasil dari simulasi dapat menunjukkan ciri-ciri

bendalir tersebut seperti pemisahan aliran dan akan dibanding dengan imej yang

diperoleh dari ujian terowong angin yang dijana menggunakan penjana asap.

viii

TABLE OF CONTENT

CHAPTER TITLE

PAGE

SUPERVISOR DECLARATION i

DECLARATION iii

DEDICATION iv

ACKNOWLEDGEMENT v

ABSTRACT vi

ABSTRAK vii

TABLE OF CONTENT viii

LIST OF FIGURE xi

LIST OF TABLE xii

LIST OF ABBREVIATION xiv

NOMENCLATURE xv

CHAPTER 1 INTRODUCTION 1

1.0 Background 1

1.1 Problem Statement 2

1.2 Objective 2

1.3 Score 3

CHAPTER 2 LITERATURE REVIEW 4

2.0 Background 4

2.1 Malaysia Weather Climate 4

2.2 Fluid Mechanic Concept 9

2.2.1 Boundary Layer 9

ix

2.2.2 Boundary Layer Type And Thickness 9

2.2.3 Turbulent Wind 11

2.2.4 External Flow : Flow Over Bodies 13

2.3 Previous Case Studies Of Solar Panel 15

2.3.1 Wind Loading On Solar Panel 15

CHAPTER 3 METHODOLOGY 20

3.0 Introduction 20

3.1 Project Flowchart 20

3.2 Determining Tilt Angles 22

3.3 Solar Photovoltaic Panel Ground Mounted Design

Concept

24

3.4 Project Component Breakdown 25

3.5 Wind Tunnel 25

3.5.1 MF134D Subsonic Wind Tunnel 26

3.5.2 Dimensional And Similarity Analysis 28

3.5.3 Determining Drag on Wall of Wind

Tunnel Section using Boundary Layer

Profile

29

3.5.4 Model Manufacturing Process 30

3.5.5 Experiment Procedure 30

3.6 Computational Fluid Dynamic 32

3.6.1 Geometry Modeling 34

3.6.2 Grid Generation (Meshing) 35

3.6.3 Set Properties, Boundary & Initial

Condition

36

3.6.4 Turbulence Modeling 37

x

CHAPTER 5 CONCLUSION AND RECOMMENDATION 52

5.0 Conclusion 52

5.1 Recommendation and Improvement for Better

Result

53

REFERENCES 54

BIBLIOGRAPHY 56

APPENDIX 57

CHAPTER 4 RESULT AND DISCUSSION 38

4.0 Background 38

4.1 Result 38

4.1.1 Computational Fluid Dynamic 39

4.1.2 Wind Tunnel Experiment Result 40

4.2 Visual Display Result Analysis 41

4.2.1 Computational Fluid Dynamic 41

4.2.2 Wind Tunnel 44

4.3 Discussion 46

xi

LIST OF FIGURE

LIST TITLE PAGE

Figure 2.1 Malaysia Climate change graph for 2010 6

Figure 2.2 Aftermath of violent wind in Pandamaran, Klang 21

October 2014

7

Figure 2.3 Small scale tornado in Kedah 12 November 2014 8

Figure 2.4 Profile of boundary layer 10

Figure 2.5 Turbulent Flow over flat plate 11

Figure 2.6 Example of turbulent wind phenomenon over an obstacle 12

Figure 2.7 Mean velocity contour developed in the simulation 16

Figure 2.8 The air flow around the panel surface and the generation

of resultant pressure coefficient, CLR

18

Figure 3.1 Project Flow Chart 21

Figure 3.2 Solar Altitude and Azimuthal Angle (γ) 22

Figure 3.3 Chosen Solar Panel Ground Mounted Design 24

Figure 3.4 Wind load on solar panel detail project breakdown 25

Figure 3.5 MF134D Subsonic Wind Tunnel 26

Figure 3.6 Speed Control And Indicator Module of Wind Tunnel 26

Figure 3.7 Setting Solar Panel onto the Test Section 31

Figure 3.8 Steps in CFD Simulation 33

Figure 3.9 Description of models in WorkBench 34

Figure 3.10 Meshing of the panel 35

Figure 4.1 Convergence of 15° Inclination Angle Model 39

Figure 4.2 Velocity Contour for 10° Inclination Angle 41

Figure 4.3 Velocity Contour for 15° Inclination Angle 42

xii

Figure 4.4 Velocity Contour for 20° Inclination Angle 42

Figure 4.5 Flow Pattern of 10° Inclination Angle 44

Figure 4.6 Flow Pattern of 15° Inclination Angle 44

Figure 4.7 Flow Pattern of 20° Inclination Angle 45

Figure 4.8 Graph of Drag Force against Inclination Angle 47

Figure 4.9 Graph of Drag Coefficient against Inclination Angle 48

Figure 4.10 Graph of Lift Force against Inclination Angle 49

Figure 4.11 Graph of Lift Coefficient against Inclination Angle 50

xiii

LIST OF TABLE

LIST TITLE PAGE

Table 1.1 Annual Solar Radiation for Towns in Malaysia 5

Table 3.1 The Value of Properties set in CFD setup 36

Table 4.1 Parameter Condition 38

Table 4.2 Result for CFD with Inclination Angle 39

Table 4.3 Wind Tunnel Experimental Result 40

xiv

LIST OF ABBREVIATION

PV Photovoltaic

CFD Computational Fluid Dynamic

HVAC Heating, Ventilation and Air Conditioning

RE Reynold Number

RMS Root-mean-square

LES Large Eddy Simulation

NBCC National Building Code of Canada

RANS Reynold Average Navier Stoke Equation

RNG Re-Normalisation Group

KMK Kompleks Makmal Kejuruteraan

ASCE American Society of Civil Engineer

SR EN Asociatia de Standardizare din Romania

SIMPLE Semi-Implicit Method for Pressure Linked Equation

2D Two Dimensional

3D Three Dimensional

xv

NOMENCLATURE

δ = Boundary layer thickness (m)

V = Velocity (m/s)

ρ = Density (kg/m3)

γ = Azimuth angle (°)

Π = Dependent variable

L = Characteristic length based on shape (m)

P = Pressure (Pa)

CL = Lift Coefficient

CD = Drag Coefficient

FD = Drag Force (N)

FL = Lift Force (N)

FR = Summation of drag force and lift force (total force) (N)

v = Kinematic viscosity (m2/s)

𝜏𝑤 = Shear stress boundary layer

A = Planform area (m2)

θ = Momentum thickness of boundary layer

k = Turbulent kinetic energy

ε = Dissipation rate of k (eddy dissipation)

Aref = Reference area of a structure (m2)

Fw = Wind Force (N)

Cs, CD = Structure Coefficient (Romanian Standard)

ρ = Atmospheric Air Density (kg/m3)

µ = Air Viscosity (kg/ms)

Hz = Frequency

xvi

LIST OF APPENDIX

LIST TITLE PAGE

A1 GANTT CHART PSM 1 57

A2 GANTT CHART PSM 2 58

1

CHAPTER 1

INTRODUCTION

1.0 BACKGROUND

Solar energy is the most considerable and abundant energy source in the world

and emits approximately 1353W/m2 on to the surface. The world receives 170 trillion

kW of solar energy but in portion, 30% of this energy is reflected back to the space,

47% is transformed to heat energy, 23% is used for evaporation cycle, and 0.5% is used

in the kinetic energy of the wind, waves and photosynthesis of plants. Photovoltaic

system converts sunlight directly into electricity.

Solar photovoltaic system consists of cells which are the building block of the

system. Module or panels are made up of multiple cells and array typically made up

from multiple modules. Solar photovoltaic application can be found in spacecraft,

commercial or domestic uses. Photovoltaic system has two types which is stand alone

and grid connection. Wind is defined as air in moving motion. Any body that stop,

deflects or change the kinetic energy of wind into potential energy creating a force

called wind load. High velocity wind can be very destructive and dangerous thus wind

load studies on structural integrity of the solar panel are very important.

2

1.1 PROBLEM STATEMENT

The evaluation and understanding of wind load applied on solar photovoltaic

panels are crucial for design purpose as extreme wind event especially cyclone and

monsoon season give challenges in designing solar panel. Concerns about structure

strength of solar panel to withstand high wind loads has become a priority as

aerodynamic forces acting on solar panel can cause serious mechanical damage to the

structure which can lead to reduced efficiency. The consumer may subject to

unreasonable, costly maintenance and unnecessary replacement.

In the past years, varies of solar-related technologies in the market but number

of study exist regarding aerodynamic subject on solar panels especially Malaysia can be

considered miniscule. As stated by the Building Research Establishment Digest for

British Standard, “there is very little information and no authoritative guidance about

wind loads on roof based photovoltaic systems” [Blackmore 2004] .Lack of clear

guidelines on wind loading forces the engineers to do assumption of wind load

coefficient when designing solar panels using standard that were made for structures

like carport, fences, billboard and heating, ventilation and air conditioning (HVAC)

units. It resulted in poor safety and uneconomical design.

1.2 OBJECTIVE

I. To investigate the aerodynamic feature on ground mounted solar panel

system at different inclination angle.

II. To compare the wind load studies on solar panel between wind tunnel

and by computational fluid dynamics simulation.

3

1.3 SCOPE

The focus of this study is mainly about wind loading on solar PV panels at

different inclination angle. Investigation of wind flow, drag force, lift force and pressure

distribution will be determines and how the aerodynamics load affects the solar

photovoltaic panels. For experimental method, wind tunnel testing will be perform

using small scale models of panels with atmospheric boundary layer flow representing

open terrain condition with tilt angles of 10°,15° and 20°. For simulation case, CFD

ANSYS FLUENT will be employ to examine the fluid flow.

4

CHAPTER 2

LITERATURE REVIEW

2.0 BACKGROUND

This chapter is a summary of fluid flow concept and previous studies on wind

loading on solar panels. Malaysia’s wind conditions in the year of 2014 were introduced

in the first section. The fluid mechanics concept of boundary layer and their

characteristic also described. Wind tunnel testing and computational fluid dynamics are

briefly explained alongside the studies itself which is the wind effect on solar panels are

written in the last section of this chapter.

2.1 MALAYSIAN WEATHER CLIMATE

Malaysia is a blessed country located between 1° and 7° North Equator, with its

own characteristic of wind speed, cloud, rain distribution and humidity level. There is a

plentiful rainfall that happens due to the convection of air and thunderstorm can occur

nearly everyday. Malaysian temperature is high all year with the exception of wet season

and high altitude places. Conclusively, Malaysia, a tropical place experienced two seasons

only and that is wet and dry. However, places that located near the Equator are wet and

humid throughout the year depending on certain factor such as the distance from a place to

the ocean. The abundant rainfall and humidity means that the tropical climate is not the

hottest but still it receives considerable sunshine. Table 2.1 show the annual solar radiation

receives in major towns in Malaysia.

5

Table 2.1: Annual Solar Radiation for towns in Malaysia (http://www.seeforum.net/sustainableenergyandenvironment)

It has all these renewable energy resources in abundance, but most of these

renewable energies are still in introduction phase. In Malaysia, the climate conditions are

favorable for the development of solar energy due to the large source of solar radiation.

With the average daily temperature of 27.5°C, 2228 hours of sunlight per year with an

average of 6.1 hours of sunlight per day and range between 4.9 hours per day in November

and 7.4 hours per day in February [Rosli, 2010] .The solar radiation ranging from

6.5kWh/m2 in the months of January and drops lower to 6.0kWh/m2 in the months of

August. As a result, the solar radiation in Malaysia is high by world standards [Mohammad

et al, 2006].

6

Figure 2.1: Malaysia climate change graph for 2010

(http://www.climatetemp.info/Malaysia, 2010)

Figure 2.1 shows the graph of climate change in 2010. The main wind direction is

variable and the mean surface winds over peninsular Malaysia are generally mild, with

the highest mean daily wind speed of about 3.8 m/s measured at Mersing, and a highest

maximum wind speed ever recorded was 41.7 m/s at Kuching. Malaysia experienced

four monsoon seasons throughout the whole year.

• The southwest monsoon season happens between May to early June and ends in

September. The wind flow is generally southwesterly and light, below 15 knots

(7.71 m/s)

• The northeast monsoon season occurs in November until March. During this

season, steady easterly or northeasterly winds blows of 10 (5.14 m/s) to 20 knots

7

(10.28 m/s). The winds over the east coast of Peninsular Malaysia may reach 30

knots (15.42 m/s) or more.

However for the past few months in 2014, Malaysia has witnessed few violent wind

and small scale tornadoes in multiple places such as Pandamaran, Klang and Kedah.

Figure 2.2: Aftermath of Violent Wind in Pandamaran, Klang 21 October 2014

(http://www.bharian.com)