DEVELOPMENT OF A LOW COST H - DARRIEUS ROTOR BLADE FOR A SMALL VERTICAL AXIS WIND TURBINE HAROUB AHMED HAROUB MASTER OF SCIENCE (Energy Technology) JOMO KENYATTA UNIVERSITY OF AGRICULTURE AND TECHNOLOGY 2015 Development of a Low Cost H - Darrieus Rotor Blade for A Small Vertical Axis Wind Turbine Haroub Ahmed Haroub A Thesis Submitted in Partial Fulfilment for the Degree of Master of Science in Energy Technology in the Jomo Kenyatta University of Agriculture and Technology 2015 DECLARATION This thesis is my original work and has not been presented for a degree in any other University Signature ………………………………................ Date…………………………. Haroub Ahmed Haroub This thesis has been submitted for examination with our approval as University Supervisors. Signature Date 13th September, 2016 Mr. Francis Xavier Ochieng’ IEET - JKUAT, Kenya Signature ………………………………............. Date…………………………. Dr. Joseph N. Kamau JKUAT, Kenya ii DEDICATION This work is dedicated to my dear parents; My Dad Ahmed Sheikh Harub and my Mum Lula Abdirahman. Thank you for your love and support. iii ACKNOWLEDGMENT I would like to express my sincere gratitude to my supervisors, Mr. Francis Xavier Ochieng ‘and Dr. Joseph Kamau for the leadership and guidance they gave me during my studies and writing of this thesis. I appreciate their support and dedication for the valuable hours we spent together discussing about my work and the chapters of this thesis. I would in particular like to thank the Jomo Kenyatta University of Agriculture and Technology (JKUAT), especially the Institute of Energy and Environmental Technology (IEET) Director, Prof Kinyua and members of his staff. The laboratory technicians and the research assistants at IEET did a wonderful job during the laboratory work and I sincerely thank them. My daughter Hala, my wife Salwa, my dear friend, my classmates, colleagues and my family kept on encouraging me and greatly contributed in the necessary moral support and I thank them for this I would also wish to sincerely thank the National Commission for Science, Technology and Innovation (NACOSTI) and the Bright Project under the wind turbine project for supporting and funding this project. iv TABLE OF CONTENTS DECLARATION ....................................................................................................... II DEDICATION .......................................................................................................... III ACKNOWLEDGMENT ......................................................................................... IV TABLE OF CONTENTS .......................................................................................... V LIST OF TABLES ................................................................................................... IX LIST OF FIGURES .................................................................................................. X LIST OF APPENDICES ...................................................................................... XIII LIST OF ABBREVIATIONS .............................................................................. XIV LIST OF NOMENCLATURE ............................................................................... XV ABSTRACT. ........................................................................................................ XVII CHAPTER ONE ........................................................................................................ 1 INTRODUCTION ...................................................................................................... 1 1.1 Background to Study .......................................................................................... 1 1.2 Statement of the Problem ................................................................................... 4 1.3 Justification of the Study .................................................................................... 4 1.4 Hypothesis .......................................................................................................... 6 1.5 Objectives ........................................................................................................... 6 1.5.1 Main objective ............................................................................................. 6 1.5.2 Specific objective ......................................................................................... 6 v 1.6 Scope of study .................................................................................................... 6 1.7 Thesis Outline ..................................................................................................... 7 CHAPTER TWO ....................................................................................................... 8 LITERATURE REVIEW .......................................................................................... 8 2.1 Introduction ........................................................................................................ 8 2.2 Wind Turbine Types ........................................................................................... 8 2.1.1 Horizontal Axis Wind Turbines ................................................................. 10 2.1.2 Vertical Axis Wind Turbines ..................................................................... 12 2.3 Materials for small wind turbine manufacture ................................................. 15 2.2.1 Metal .......................................................................................................... 16 2.2.2 Glass and carbon fibre composites ............................................................ 16 2.2.3 Wood and bamboo ..................................................................................... 17 2.2.4 Biocomposites ............................................................................................ 18 2.4 Manufacturing of small wind turbine blades .................................................... 19 2.5 How Wind Energy is harnessed ....................................................................... 20 2.6 How Turbines Work ......................................................................................... 20 MATERIALS AND METHODS ............................................................................ 23 3.1 Theory and Design Optimization ..................................................................... 23 3.1.1 Turbine size as a function of power required ............................................ 23 3.1.2 Turbine Solidity as a Function of TSR ...................................................... 26 3.1.3 Turbine Model Calculation ........................................................................ 27 3.1.4 Rotor design Process .................................................................................. 31 3.1.5 Fixed parameters ........................................................................................ 31 vi 3.1.6 Qblade modelling software ........................................................................ 32 3.1.7 Designing of the Rotor Blade .................................................................... 33 3.1.8 Aerofoil selection ....................................................................................... 35 3.1.9 Optimizing Solidity.................................................................................... 36 3.1.10 Optimizing fixed blade pitch ................................................................... 37 3.1.11 Rotor dimensions ..................................................................................... 39 3.1.12 Initial angle of attack ............................................................................... 42 3.1.13 Rotor Configuration ................................................................................. 43 3.1.14 Final Prototype Design ............................................................................ 43 3.2 Fabrication of the Full Scale Turbine ............................................................... 47 3.2.1 Activities and Components ........................................................................ 47 3.2.2 CAD Drawings and Blade airfoil............................................................... 47 3.2.3 Steel Base ................................................................................................... 51 3.2.4 Shaft ........................................................................................................... 51 3.2.5 Bearings ..................................................................................................... 52 3.2.6 Connecting arms ........................................................................................ 52 3.2.7 Tooling ....................................................................................................... 53 3.2.8 Selected Rotor Blade Material ................................................................... 53 3.2.9 GFRP Rotor Blade Production .................................................................. 55 3.2.10 Structural Analysis ................................................................................... 58 3.2.11 Generator ................................................................................................. 59 CHAPTER FOUR .................................................................................................... 62 RESULTS AND DISCUSSION .............................................................................. 62 vii 4.1 Introduction ...................................................................................................... 62 4.1.1 Experimental Set Up .................................................................................. 62 4.1.2 Observation ................................................................................................ 65 4.2 Viability of the VAWT ..................................................................................... 74 4.3 Cost-benefit analysis ........................................................................................ 77 4.4 Social and Environmental Impact .................................................................... 81 CHAPTER FIVE ...................................................................................................... 82 CONCLUSIONS AND RECOMMENDATIONS ................................................. 82 5.1 Conclusions ...................................................................................................... 82 5.2 Recommendations ............................................................................................ 83 REFERENCES ......................................................................................................... 84 APPENDICES .......................................................................................................... 89 viii LIST OF TABLES Table 3.1 : Typical Cp values for various wind turbines .......................................... 25 Table 3.2: Typical Kenyan household energy demand ............................................. 34 Table 3.3: Selected design parameters ...................................................................... 35 Table 4.4: Chosen wind turbine sizing ...................................................................... 44 Table 3.5: Generator main parameters ...................................................................... 60 Table 4. 1: Power at different wind speeds and RPM .............................................. 66 Table 4.2: Main power providers in isolated areas of Kenya.................................... 75 Table 4.3: Characteristics of the different SWT types on the Kenyan market.......... 75 Table 4.4: Cost description for developing the darrieus turbine ............................... 76 Table 4.5: List of current wind turbine models in the Kenyan Market ..................... 79 ix