The cyclical pitch vertical axis wind turbine

Abstract

My interest in wind power started from my fascination of old multi-bladed farm mills which are so common in our country side. This fascination manifested itself at first in photographing these water pumping mills on various amount of occasions. Interest in wind power was then enhanced in the course of my studies. It was during my studies that the principle of the Darrieus vertical axis wind turbine caught my imagination, and was determined to prove its worth and eliminate any possible inefficiencies. This project was thus born out of the curiosity I had on whether a Darrieus rotor would in fact be rid of its stall at low tip speed ratios. As a firm believer in its principle of operation, I was determined to prove that this wind turbine was the closest one can get to the theoretical maximum Betz efficiency (59.3% ). During my travels in Europe, I went to see a Dutch friend of mine from Eindhoven, and as all typical Dutch people, he was veiy proud of the numerous windmills that enhance his country's countryside. This was the final spark I needed. I visited an actual operating windmill (all of which are owned by the local baker who uses them to grind his grain for flour production) on a moderately windy day and was amazed at the power generated What amazed me most was that The Netherlands is an extremely flat country and still, even though the wind could not be accelerated once it reach the land from sea, there was still enough power in it to power all the turbines present. On the other hand, Malta has ideal roundish hills and being so small everywhere in Malta is close to the sea and even though we are in an ideal geographic position for the occurrence of winds, little such use is made of this free source of power. This project brings the wind energy issue into perspective. The Cyclical Pitch VAWT provides a simple method by which, by careful design, a vertical axis Darrieus rotor can rid of its stall region. Great pains were taken to finish the project in the limited time available, and even though there was much more work then originally conceived, the objectives of this project were achieved. Research, however, must not stop here, for various tests must be made to fully understand the performance of such a system. One may here note that as with regards to the actual construction, use of the best (and usually most expensive) materials were used but the end result is one of qualify. This thesis is written in exactly the same order I have proceeded with during the course of its completion. Great care was taken to simplify the understanding of the principles involved; however one must take note of the very particular details which are instrumental [...].