Development of small wind turbines for isolated Colonia homes of South Texas

Abstract

To expose the high school students to renewable energy, a project to build wind turbines exclusively by the high school students was conceived and implemented in a South Texas high school. A key motivation of the project was to make high school students interested in engineering by letting them build a complete system that harnesses wind power. The proposed system converts, stores, and measures all pertinent energy parameters for future usage. Twenty two students worked together as a team and shared all the engineering and budgetary responsibilities. An important societal component was added to the project by identifying the potential of small wind turbines to meet, at least partially, the energy need for isolated, off-grid poor residents in Colonias of South Texas. A challenge was made to the students; namely, how to supply electricity to poor residents in isolated, off-grid Colonias. They were asked to analyze the need, identify a solution, and finally, deliver it. Important major restrictions for the students included an easy to follow engineering build, $1500 dollar limit for the turbine parts, no outside help, and commercially available parts. None of the authors were involved in manufacturing the turbine. A total of 22 students, 14 boys and 8 girls, participated in this program. The team had a Team Leader, a girl, and four Team Captains. The team was trained by one of the authors on all science and engineering aspects of wind turbine. Another author trained them in blade carving and aerodynamics. One of the teachers from the high school kept a watchful eye for day to day activities of the students, mostly for safety reasons. Hugh Piggott's book on the subject was given to the students as a guideline. Final product was a 30' tall tower with three 8' diameter pine wood turbine and 12 Neodymium Iron Boron permanent magnets. The system also included 1200 Watt Whistler power inverter, Xantrex charge controller, and a DC heater as dump load. Four deep cycle Werker 6 VDC output batteries were used to store the wind power to deliver at 12 VDC when needed. Finally, the students also added a HOBO data logger to collect pertinent wind data. Estimated "sweat equity" for the system built was 150 person-hours, a doable effort for Colonia residents. While the turbine was not able to generate enough power for the lofty goal of electrifying a Colonia home, it was an excellent start for the students to be sensitive to local societal needs and the sense of achievement by developing and delivering an engineering solution to the problem. Students also learnt a lot of about renewable energy and many concerns of the local Colonia residents. Finally, it left a legacy of excitement and hope for the next group of students to further refine the solution. Twenty of the twenty two students, including two who changed their education path to engineering, joined science or engineering degree programs after graduation from this program. © 2012 American Society for Engineering Education.