DEVELOPMENT OF A LOW COST, LOCALLY MANUFACTURED ROTOR BLADE FOR A SAVONIUS WIND PUMP

Abstract

Studies indicate that vertical axis wind turbine provide a more reliable energy conversion technology, as compared to horizontal axis wind turbine, especially in areas of lowly rated and/or uncertain wind speeds, mostly arid and semi-arid areas. The challenge however is the development of an efficient and cheap rotor blade which is currently not manufactured in Kenya. The objective of this research was to identify local wind turbines manufactures in Kenya; design a savonius rotor blade; locally develop a Savonius vertical axis wind turbine rotor blade for wider use in Kenya and to analyze the cost of the developed Savonius rotor blade. In achieving these, a number of methodologies including: field questionnaires, empirical design calculations, prototype development and laboratory testing were used to develop such a rotor blade. Laboratory tests using a tachometer and Hygro- thermometer were able to provide a number of interesting results including: Ability to pump water of four cubic meter per day for 200 people, costing less than KES 300,000/= per unit and hydraulic power capability of less than 1 kW. Field tests for the system are to be undertaken soon but it is projected that the laboratory results will not differ significantly from the field results. In conclusion the research work has been able to develop a wind conversion technology that makes the system affordable, locally manufactured and more efficient than current existing system. A key achievement of the system has been the ability to provide the local small wind energy sector a process and material matrix to be used in developing of more efficient vertical axis wind turbine blades that are more adaptable towards Kenya’s average wind speed of ≤ 4m/s.