Re ECF Project: 2007-06

Project Title: Investigation on the feasibility and enhancement methods of wind power utilization in high-rise buildings of Hong Kong

Applicant: The Hong Kong Polytechnic University (Dr. Lu Lin, Vivien)

Total Approved Grant: $130,000 (ECF & WWGF: 50/50)

Duration: 01/03/2008 to 31/8/2009

Project Status/Remarks: Completed

The objectives of the study are: to investigate the wind aerodynamics and wind flows over the buildings in the urban areas; and to evaluate local wind power; to address the strategies how to develop wind power in local urban areas more effectively; to investigate and propose the optimal roof shape in favor of wind power application; to study the buildings as a concentrator of the wind for the Building Augmented Wind Turbines (BAWT); and to propose the utilization of the concentration effect of buildings; and to provide informative data for concerned parties.

Summary of the Findings/Outcomes:
A reference building was chosen to investigate the wind power utilization in high-rise buildings in Hong Kong. To achieve reasonable and practical inlet conditions for the wind flow simulation over the reference building, the long-term wind data from two weather stations, the Waglan Island and HKO (TST), were analysed considering their wind direction and wind speed distribution.

The dominant wind flows from the East in Hong Kong, and the wind speed distribution are totally different for the two weather stations due to different surrounding environments. Taking the wind from the East with wind speeds of 5m/s, 6m/s and 7m/s as the inlet input of the developed building model, the wind velocity and wind power distribution are simulated. It concludes that the building concentration effect can increase the wind power significantly, such as 5.43 times at 4m above the building roof. For different wind speeds, the enhancement effect is different. Meanwhile, turbulence and low velocity areas could be also caused due to existence of buildings. After the velocity comparison, four wind directions including East, West, South, and North are also chosen to simulate and analyse the wind distribution.

All the cases of different wind directions have found that a low velocity area above the roof is very small, i.e. the building roof has a high potential of wind power. The height of the low velocity area can be overcome by the typical lift pole of the wind turbine installation. Also, the out area of the building roof owns more advantage of wind power utilization. Wind power utilization in high-rise buildings in Hong Kong is very promising. The tool of Computational Fluid Dynamics (CFD) is recommended to be used to model the annual wind flows over buildings to help analyse, locate, and design wind turbines in and around buildings.