Design of a Low Head Pico Hydro Turbine for Rural Electrification in Cameroon by Bryan Patrick Ho-Yan A Thesis presented to The University of Guelph In partial fulfilment of requirements for the degree of Master of Applied Science in Engineering and International Development Guelph, Ontario, Canada © Bryan Patrick Ho-Yan, April, 2012 ABSTRACT DESIGN OF A PICO HYDRO TURBINE FOR RURAL ELECTRIFICATION IN CAMEROON Bryan Patrick Ho-Yan Advisor: University of Guelph, 2012 Professor W. D. Lubitz Rural areas of Cameroon have limited to no availability of grid-supplied electricity, however many locations have significant hydro potential. Pico hydro (less than 5 kW generation capacity) has been identified as a promising means for rural electrification. Tests of previously implemented designs and field research in Cameroon were conducted to contextualize the design process. Field research involved end-user and artisan interviews, market research, site investigations, and artisan collaboration. Findings were used to select an axial flow propeller for the improved turbine. Detailed design used turbomachinery theory towards the development of a locally manufactured low head pico hydro turbine for rural electrification. A propeller turbine with complex blade geometries was designed but simplified to incorporate flat blade geometries to better suit the local manufacture capabilities. A prototype turbine was built and tested. The flat blade propeller turbine performed reasonably well, but was unable to achieve desired power generation targets with predefined head and flow rate conditions. Dedication and Acknowledgements This thesis is dedicated to my wife, Annie, who has never stopped encouraging me throughout this endeavour and constantly inspires me through her love and integrity. And also to my daughters, Blythe and Abbey, for keeping me on my toes and inspiring me to never stop learning. I would like to express my gratitude to my graduate advisor, Dr. William David Lubitz for the opportunity to define my research and run with it. Through his guidance and openness he has strengthened this work. My appreciation also goes to Dr. Warren Stiver for his insights and strong support for this project. This research would not exist without the leadership and hard work of Johannes Hertlein, Cornelia Ehlers, and Edwin Njonguo of GREEN STEP e.V. I am always amazed by their enthusiasm and their ability to make things happen. My appreciation goes to them for showing me the beauties of Cameroon. Many thanks go to Dr. Stephan Krebs, Johannes Urban, Petra Kuerzinger, Gerald Schickhuber, and Björn Pucher for sharing their invaluable ideas with me. I must acknowledge my friends and research colleagues in Engineering and International Development specifically Qiyue Song, Rajendra Sapkota, and Murray Lyons for their help with research and the test rig setup, and Joel Citulski, Graham Aikenhead, Maxime Moisan, Nitin Seth, and Stephanie Shaw for going through this whole adventure with me. I am grateful for the technical and administrative support from the University of Guelph staff, namely Ken Graham, Steve Wilson, Barry Verspagen, Nate Groendyck, John Whiteside, Mary Payne, Phil Watson, Lucy Cremasco, Alex Galvez, Martha Davies, and Laurie Gallinger. And a final thank you to my professors at the University of Guelph for opening my eyes to the complexities of development from all disciplines and perspectives and for teaching me about how little we know. This research was supported by the Natural Sciences and Engineering Research Council (NSERC) Chair in Environmental Design Engineering at the University of Guelph. iii Table of Contents Dedication and Acknowledgements............................................................................................... iii Nomenclature ............................................................................................................................... viii Glossary of Terms .......................................................................................................................... xi 1.0 Project Environment........................................................................................................... 1 1.1 Rural Electrification....................................................................................................... 1 1.1.1 The Current State of Rural Electrification................................................................. 1 1.1.2 Rural Electrification Options..................................................................................... 2 1.1.3 Benefits of Rural Electrification................................................................................ 2 1.1.4 Applications of Rural Electrification......................................................................... 4 1.1.5 Challenges of Rural Electrification............................................................................ 5 1.2 Cameroon....................................................................................................................... 5 1.2.1 Geography ................................................................................................................. 6 1.2.2 History ....................................................................................................................... 6 1.2.3 Corruption.................................................................................................................. 7 1.2.4 Economics ................................................................................................................. 8 1.2.5 Energy........................................................................................................................ 8 2.0 Pico Hydro........................................................................................................................ 10 2.1 Pico Hydro for Development ....................................................................................... 10 2.2 General Pico Hydro Principles..................................................................................... 13 2.3 System Components..................................................................................................... 14 2.3.1 Forebay.................................................................................................................... 14 2.3.2 Penstock................................................................................................................... 14 2.3.3 Turbine..................................................................................................................... 15 2.3.4 Draft Tube................................................................................................................ 16 2.3.5 Electrical System ..................................................................................................... 17 2.4 Pico Hydro Turbine Technology.................................................................................. 17 2.4.1 High Head................................................................................................................ 17 2.4.2 Medium Head .......................................................................................................... 19 2.4.3 Low Head ................................................................................................................ 21 2.5 Pico Hydro in Cameroon.............................................................................................. 27 2.6 Turbine Theory ............................................................................................................ 27 2.6.1 Specific Speed and Specific Diameter..................................................................... 27 2.6.2 Euler Turbomachinery Equation.............................................................................. 30 2.6.3 Velocity Diagrams................................................................................................... 31 2.6.4 Blade Cascade Geometry......................................................................................... 33 3.0 Problem Statement ........................................................................................................... 34 3.1 Problem Statement and Significance ........................................................................... 34 3.2 Affiliates ...................................................................................................................... 35 3.3 Scope of Work ............................................................................................................. 37 4.0 Baseline Investigation ...................................................................................................... 38 4.1.1 Baseline Construction - Firefly................................................................................ 39 4.1.2 Baseline Test Apparatus .......................................................................................... 40 4.1.3 Baseline Test Method .............................................................................................. 41 4.1.4 Baseline Test Results............................................................................................... 42 4.1.5 Baseline Test Discussion......................................................................................... 43 5.0 Technology Selection and Concept Designs .................................................................... 45 5.1 Technology Selection..................................................................................................