Design and construction of a small multi-bladed wind turbine for the suburban and rural environments

Abstract

The Maltese countryside is still dotted with a number of American style wind-driven water pumps which were used to extract water from the aquifer for irrigation purposes. Many of these machines have fallen into disuse as electrification has taken over. In some cases, the only remaining component is the lattice tower. These machines are now acknowledged landmarks of the Maltese rural landscape. The idea behind this current initiative is to use the existing wind pump towers and to replace their old rotors with a new turbine design. Field surveys were carried out in order to estimate the structural integrity of the existing towers, the number of towers available and their distribution over the Maltese islands. A multi-bladed, 3.4 metre rotor diameter wind turbine capable of generating electricity andhaving a higher aerodynamic efficiency was designed to aesthetically resemble the original wind driven water pumps. The new wind turbine blades were fabricated from glass fibre reinforced polyester composite and have been tested to MSA EN 61400 Part 2:2006. The rotor is aligned to face the wind direction by means of a tail vane. The yaw shaft is slightly misaligned from the longitudinal axis of the main driveshaft in order to protect the turbine in high winds through passive vaw control.