Bahrain World Trade Center

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Bahrain World Trade Center
BWTC
Bahrain World Trade Center
Bahrain World Trade Center
Bahrain World Trade Center

BWTC logo
Basic data
Place: Manama , Bahrain
Construction time : 2004-2008
Opening: 2008
Status : Built
Architects : WS Atkins PLC
Technical specifications
Height : 240 m
Height to the top: 240 m
Rank (height) : 2nd place (Bahrain)
2nd place (Manama)
Floors : 50
Elevators : 4th
Building-costs: $ 150,000,000 
Height comparison
Manama : 2. ( list )
Bahrain : 2. ( list )
address
City: Manama
Country: Bahrain

The Bahrain World Trade Center , BWTC for short, is a building in Bahrain's capital, Manama . It consists of two main towers that are connected to one another by means of three cross braces. Each of the two sail-shaped buildings reaches a height of 240 meters with 50 floors (34 of which are for offices). There is a shopping hall under the building. A special feature of the skyscraper are three wind turbines mounted on the cross braces , making the Bahrain WTC the world's first high-rise with an integrated wind turbine. It belongs to the World Trade Centers Association . The construction of another, but completely energy self-sufficient skyscraper in Bahrain - the 322 meter high Burj al-Taqa - is planned.

location

The building, which consists of two towers connected by three inaccessible bridges, is located near the Persian Gulf . It is the second tallest building in Bahrain after the Bahrain Financial Harbor (260 meters, 54 floors) . According to official information, it is a 15-minute drive from Bahrain International Airport .

Construction and history

Construction work on the Bahrain World Trade Center began in August 2004 after three years of planning. After six months the first five floors were already up and after two years of construction the final height of 240 meters was reached. Then the third cross brace was pulled up and installed. After this action, the generators were attached to the cross struts, then rotors were assembled on the ground, transported up and also mounted. On March 19, 2007, the first, lowest wind turbine was installed, then the middle and the top one. Then the crane for lifting the wind turbines and cross bracing, which was attached between the two building halves, could be dismantled again. On September 11, 2007, all 50 floors were completed. The first, bottom wind turbine has been supplying electricity since August 8, 2008, the middle one followed a month later, the top one another later.

The National Commercial Bank of Saudi Arabia announced in July 2006 that it was moving its headquarters to the Bahrain World Trade Center.

Buildings and integrated wind turbines

Technical data of the wind turbine

A special feature are three wind turbines integrated into the building. Between 11 and 15 percent of the energy demand is to be covered by wind energy . In total, the 3 wind turbines deliver around 1.1–1.3 GWh of electrical energy per year . The wind turbines attached to three cross struts between the towers each have a rotor diameter of 29 meters. This makes them the world's first building-integrated wind turbine energy system. The 34 meter distance between the two towers counteract the diameter. While the distance between the two skyscrapers at the front of the building complex is 126 meters, at the end of the building it is only 33 meters. At full capacity, the rotors from Denmark reach a speed of 38 revolutions per minute. Each system weighs 11 tons, with the generator accounting for 6.5 tons. The top wind turbine is at a height of 133 meters.

Aerodynamics and efficiency of wind turbines

Critics point out, however, that the fixed propellers also have to cope with eddies, updrafts and downdrafts and cannot turn in the direction of the wind, which means that the power yield would be lower than planned. But attempts have been made to counteract this. The double building should act like a wind concentrator . The shape and arrangement of the two towers play a role here. Their bases are oval, and the two halves of the building are not parallel, but are arranged in a funnel shape so that the distance between the two halves of the building varies between 126 meters and 33 meters. At the end of this "funnel" are the three bridges with the wind turbines. The oval shape, which is modeled on the profile of airplane wings, and the funnel-shaped arrangement of the towers ensure that wind from the side hits the wind turbines at a right angle, if possible . In the meantime, engineers have proven through computer simulations and tests in wind tunnels that the special sail-like shape of the towers separated from each other means that the wind could also come from an angle of 75 degrees so that the wind turbines can rotate.

Since the wind speeds are higher at high altitudes and the uppermost turbines would be more susceptible to damage, the building tapers upwards so that the wind is less concentrated on the wind turbines above than in the lower area.

safety

Since rotating parts on a building do not necessarily support its safety, special measures have also been taken here so that the building can withstand wind speeds of up to 250  km / h without damage. The rotatable tips of each rotor blade ensure that the wind turbines do not become a hazard with such a rotor blade. If the wind speed is too high, they can be tilted so that they offer the wind as little resistance as possible. If a rotor blade should ever separate from the wind turbine, steel cables attached to the interior of the wind turbine prevent it from endangering one of the two office towers or the shopping center below the wind turbines.

So that the rotors do not damage the rest of the system, they are usually mounted on a tower with a nacelle and the rotor blades are not parallel to the tower, but are tilted by five degrees, so that a greater distance between the rotor blade tip and the tower can be achieved.

This technology cannot be used at the Bahrain World Trade Center because the turbine has two struts. Therefore, it was decided to use a positive arrow shape for the cross bracing. The wind turbines are then attached to the tip end of the “V”, so that a distance of 1.7 meters was achieved between the tip of the rotor blade and the cross strut.

Another problem is that the buildings sway with high wind speeds. Fixed connections between the two towers could then lead to tension. In order to prevent this, it was decided to only mount the cross bracing firmly on one side, while on the other side it is only attached to the other building on steel rollers - i.e. movable.

additional

However, the building should not only be more climate-friendly thanks to the wind turbines. It also has double-glazed windows, which reflect up to 85 percent of the heat rays coming from outside and thus place less stress on the air conditioning. The lighting and air conditioning should also be particularly efficient.

Movie

Web links

Individual references and sources

  1. ^ Burj Al-Taqa - Energy Tower. Geber Architects, accessed on September 9, 2010 .
  2. ^ Bahrain builds first wind powered towers . Reuters website. Retrieved March 11, 2016.
  3. ↑ Green giants . In: Bild der Wissenschaft 01/2008, pp. 94–99. Konradin Medien GmbH, Leinfelden-Echterdingen 2007, ISSN  0006-2375

Coordinates: 26 ° 14 '22.1 "  N , 50 ° 34' 52.7"  E