Turbines installed between towers in Bahrain

Engineers Australia
May, 2007 Page: 31

Large-scale turbine blades have been installed onto the 240m-high Bahrain World Trade Center towers by UK engineering consultant Atkins. It is one of the first buildings in the world to incorporate the feature. All major structural works have been completed on the building, which is scheduled to open this year.

The three wind turbines are horizontally supported between the towers by three bridges weighing 65t. The installation of the 29m diameter blades was the culmination of over three years of research and development by the company's architects and engineers collaborating with Danish partners Ramboll and Norwin. The Nass Murray and Roberts joint venture was the builder on the project. Atkins performed structural engineering.

"The challenge was to physically and operationally integrate the turbines and bridges into the high-rise building form," said Simha Lytherao, senior project manager for Atkins Middle East. "Physical integration meant supporting around 80t per turbine and the bridge while also mitigating imposed dynamic loads, including structure-borne vibration.

"Operational integration meant harmonising the electricity generated with the building low voltage electrical systems and coordinating the control of the turbines with the various building management systems." Once operational, the wind turbines will generate about 11 %-15% of the towers' energy needs. According to the company, this will equate to about The power will be used for the public areas of the building.

According to the company, the 50-storey towers were designed to enhance the effectiveness of the turbines housed between them. The elliptical shape of the towers causes them to behave as aerofoils, funnelling the onshore breeze between them and creating a negative pressure behind, thus accelerating the wind velocity between the towers. The effect was confirmed through wind tunnel testing and computational fluid dynamics modelling which showed the incoming wind being deflected by the towers in the form of an S-shaped streamline passing between both towers.

This funnelling has the effect of amplifying the wind speed at the turbine location by up to 30%. Vertically, as the towers taper upwards, their aerofoil sections reduce. When combined with the increasing velocity of the onshore breeze at increasing The wind turbines on the Bahrain World Trade Center will heights, this creates an almost equal regime of wind velocity for each of the three turbines.