Design and fabrication of a residential low-cost efficient horizontal axis wind turbine (HAWT)

Abstract

This project aims at designing and manufacturing an efficient low cost horizontal-axis wind turbine. The challenge is to see whether such wind turbines are feasible in Lebanon giving that the wind isnt very substantial. This study focuses on designing the blades where airfoil selection, length, tapering, twisting and pitch angles are variables. Two numerical approaches are taken: hand calculations based on velocity-triangle method using airfoil experimental charts, and 2-D CFD simulations to compare lift and drag coefficients. 3-D CFD fails to predict reasonable values as residuals dont converge properly thus the results arent taken in consideration. Structural analysis is done on both wood and a fiberglass/epoxy matrix in favor of material selection. Fiberglass/epoxy proves to be the best match. The fabrication process includes hot-wire foam cutting, mould making, fiberglass/epoxy curing, etc. The other parts of the wind turbine are fabricated/purchased according to standards. Testing in front of a proper source of wind like a wind tunnel was not possible. The turbine is tested in real wind and power output is calculated by measuring voltage and current outputs from the generators while rotational speeds of the blades are also measured. The highest power output measured was 130 W at 6.5 m/s wind speed while the highest power coefficient (CP) was around 18% at 5 m/s wind speed. The results are found to have various losses initiating from undesirable frictional losses and problems in the fabrication. However, having those errors known, the results are then compared to their respective calculated counterparts and the results showed encouraging outcome after redoing the calculations using the measured RPMs and removing the generator losses from the measured power. The predicted 500-600 W output at 8 m/s wind speed was not achieved due to the errors mentioned and also due to the fact that testing at this high speed was not done. Further testing needs to be done on the wind turbine manufactured and various improvements could be made in future projects.