Design and testing of a concentrator wind turbine

Abstract

Wind energy, being an indirect form of solar energy would initially seem a very promising form of energy. Unfortunately, it suffers from the problem of dilution. Wind turbine designers naturally try to compensate for this by increasing the size of the rotor to capture more of the kinetic energy of the wind. A major constraint in conventional wind turbine design is the reduction in rotational speed as the size of the rotor is increased. This means expensive gear boxes are unavoidable. The rotor also becomes considerably more complicated in design and heavier as the size increases, to mitigate working stresses. Flow concentrators have been investigated in an attempt to alleviate wind turbine design problems, but flow concentrators usually incur the expense of high structural weight and size. The Helical Vortex Wind Concentrator (HVWC) is a recent addition to the list of flow concentrator types and its economic potential is, as yet unknown. The principle of the HVWC has been demonstrated in a series of wind tunnel tests. The wind tunnel tests involved a direct comparison between the performance of a wind turbine with and without an HVWC attached.During these tests a definite increase in power out was observed when the concentrator was attached to the wind turbine. Previous to these successful wind tunnel tests, other wind tunnel and field tests had been conducted on less successful designs. These other tests were important in the development of the current theory and design or the HVWC. Future research will need to investigate both physical and economic limitations of this type of wind concentrator.