Performance Study and Optimization of the Zephergy Wind Turbine
There are many problems associated with small wind turbines, such as small Reynolds number and poor starting performance, that make them much more expensive than the large ones per unit power. New technologies are needed to improve the quality of these turbines and reduce their costs. This thesis investigates a novel type of small wind turbine called Zephergy. Unlike conventional wind turbines, Zephergy is composed of more than one rotor/stage. A two-stage turbine is examined here. Each stage has two inner and outer rings. The blades are designed based on the recognized principles of turbomachinery, and are mounted between the two rings. Initially, performance of each individual stage is studied and compared to the performance of Bergey XL 10 kW as a typical small-size wind turbine. Next, various experiments are performed and the results are analyzed when both stages are installed in the test section to see how the presence of one stage affects the operation of the other. Our work shows that the Zephergy wind turbine performs very well especially in terms of the efficiency and starting performance.