A review of current technical development in vertical axis wind turbine technologies and their braking system for low speed, urban and offshore areas application

Syawitri, T.P.; Yao, Y.; Chandra, B.

Abstract

Recently, there are growing interests of using Vertical Axis Wind Turbine (VAWT) to harvest wind energy from low wind speed in urban areas to relatively high wind speed in offshore wind farms. Horizontal Axis Wind Turbine (HAWT) has been known to have poor performance at low wind speed and high maintenance cost particularly in offshore wind farms. To overcome these drawbacks, VAWT concepts have been revisited because of their unique and better performance under high turbulence conditions (urban environment), lower wind speed operations (most urban areas and some offshore regions), and less wake defects (both urban environment and offshore regions). Moreover, VAWTs do not need the yaw mechanism, and the system has better stability for offshore floating application and lower risk of damaging wildlife and other living species on land and in ocean. In order to improve the performance of current VAWT design to be compatible to the HAWT, novel technologies must be developed and implemented particularly for operation conditions at low wind speed, urban and offshore environments. This paper intends to provide a thorough review of advanced and innovative technologies developed recently by focussing on two key areas: (1) the enhancement of the self-starting ability and power coefficient, and (2) the use of air-braking system instead of the mechanical-braking to simplify the design and also to protect the turbine at high wind speed above the cut-off wind speed limit. The paper starts with a survey of the state-of-the-art developments of air-braking systems for VAWTs with suggestions and recommendations on the most effective air-braking system design for performance enhancement. It continues on the discussion of the challenges of VAWTs for low wind speed, urban and offshore applications to maintain a good self-starting ability, better power coefficient at relatively light weight. Several key environmental factors are also addressed during the comparison and evaluation, including incoming flow turbulence level. The paper finally concludes that the VAWT design coupled with air-braking system of reduced weight could improve performance at undesirable low wind speed regions, thus this configuration will have great economic potentials in future, in terms of reliability, cost and ease of maintenance.

• Presentation Conference Type: Conference Paper (unpublished)
• Conference Name: International Conference of Global Warming and Climate Change 2018
• Start Date: Oct 4, 2018
• End Date: Oct 5, 2018
• Acceptance Date: Aug 20, 2018
• Peer Reviewed: Not Peer Reviewed
• Public URL: https://uwe-repository.worktribe.com/output/862839
• Additional Information: Title of Conference or Conference Proceedings : International Conference of Global Warming and Climate Change 2018