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05/11/2007 12:55 PM

Zero Emissions in the Desert

New Tower Creates All Its Own Energy

By Frank Thadeusz

A German architect is pursuing an ambitious project in the Middle East. He wants to build office towers in Riyadh, Dubai and Bahrain that produce all their own energy. The zero emissions office building has arrived.

The Middle East is home to some of the most exciting architecture in the world today. Extravagant skyscrapers are going up in the region's major cities, such as booming Dubai and Riyadh, and Abu Dhabi has plans for an ambitious museum complex.

Still, at least one sheikh was hoping for more. "Don't you have anything that is based on an interesting idea for a change?" Abdel Hadi Sadiq Pasha griped one day in a meeting. The head of the architectural unit in the general project department of Dubai municipality was complaining about brilliant architectural designs whose value is limited, at least in his view, to mere beauty.

As fate would have it, Eckhard Gerber, the man who could satisfy the sheikh's desire for innovation, was present to hear his words. Gerbel comes from Oespel-Kley, an obscure suburb of the German city of Dortmund, where he has an architecture office located in a 19th-century mansion that was once home to the area's top farming family.

A handful of architects in the old building recently dreamt up a state-of-the-art tower, a giant 68-story building projected to rise to a lofty height of 322 meters (1,056 feet), which would make it number 22 on the list of the world's tallest buildings. What is even more impressive is that not only will the Burj al-Taqa ("Energy Tower") consume very little energy -- but it will also produce all its energy itself.

"There's nothing like this in the whole world," Gerber says in praise of his own work. The architect suffers no false modesty when it comes to assessing his own project. "This kind of accomplishment is very rare," he says.

Municipalities and project developers in various Arab cities have already praised the self-sufficient eco-tower -- which exists only in digital form at present -- as "fantastic" and "brilliant," Gerber says. Gerber wants to reach an agreement with the Bahrain-based company Almoayed Holdings -- the investor that apparently wants to finance the €300 million ($406 million) project -- before the end of the year. The investor belongs to one of the five most powerful families on the island state. The German architect is also attracting the attention of financiers in Dubai and Riyadh, thanks to his high-tech tower, which is powered only by sunlight, wind and water.

Gerber is not completely unknown in the region, however. His architecture office is building both the King Fahad National Library and a science center, complete with its own shopping mall, in the Saudi Arabian capital Riyadh.

A Bold Experiment

Now, with the Burj al-Taqa, Gerber is engaging in a far bolder experiment -- one that would, however, not have been conceivable without the support of the Stuttgart engineering company DS-Plan. The architectural consultants were responsible for planning practically the building's entire technological facilities.

The outer surface is usually considered especially problematic for giant glass constructions. A study by the Darmstadt-based Institute for Housing and Environment, for example, revealed worrying conditions in German office blocks. Employees were sweltering in room temperatures well above 40 degrees Celsius (104 degrees Fahrenheit) in the summer, according to the study.

Hence the Burj al-Taqa's cylindrical shape is designed to expose as little surface area to the sun as possible. A protective solar shield reaches from the ground to the roof, covering 60 degrees of the giant circular building. It protects the side most affected from the sun's glaring rays, making sure that none of the rooms are exposed to direct sunlight. The diffuse light on the other sides of the building is tempered by a mineral coating on the windows.

The tower's façade is to be built from a new generation of vacuum glazing that will only come on the market in 2008. The new top-quality windows are meant to largely shield the interior of the tower from outside heat -- indispensable in a region where outside temperatures can reach 50 degrees Celsius (122 degrees Fahrenheit) in the summer. This is made possible by a new breakthrough in the quality of the materials used: The new vacuum glazing windows transmit as much as two thirds less heat compared to today's products.

"Such a building has to work like a thermos flask," says DS-Plan's energy manager Peter Mösle. "It has to have a cooling effect in the summer and retain heat in the winter."

Faith in German Engineering

The architects chose an ancient Persian architectural feature as their model. Hundreds of years ago, wealthy merchants erected wind towers on the roofs of their houses, an idea which was eventually exported to the Arab world. The buildings, which have now become tourist attractions, have a natural air conditioning system. Lateral openings in the towers suck in cool air like a chimney. The heavier cool air sinks down and displaces the lighter hot air, creating a comfortable temperature inside the living space despite the scorching sun.

Gerbers's design is designed to function in a similar way: The negative pressure created by winds breaking along the tower will suck the spent air from the rooms out of the building via air slits in the façade. The plan is for fresh air to be pumped into the interior of the building by means of a duct system at the same time.

Seawater will be used to pre-cool the air. Three large cooling units in the giant building's cellar will eventually lower the temperature to a comfortable 18 degrees Celsius (64.4 degrees Fahrenheit). Transparent ducts will channel the fresh air into spacious atriums and from there into the corridors and offices. The building's designers want to use high-quality steel ropes to suspend hanging gardens inside the air ducts, transforming a feature which is often regarded as an architectural blemish and hidden behind sheet metal in other buildings.

At the same time, the underground cooling center also cools the water in the pipelines running through the underside of each floor's ceiling. The system of tubes is designed to be a modern air-conditioning system which cools gently without unpleasant air currents.

However the most impressive feature of the building is that the operators of the tower will not need to use any electricity from outside sources. A 60-meter (197-feet) turbine on the tower roof and two photovoltaic facilities with a total area of 15,000 square meters (161,459 square feet) will produce sufficient electricity to meet the building's needs. Additional energy is provided by an island of solar panels with an area of 17,000 square meters (182,986 square feet), which drifts in the sea within viewing distance of the tower.

The excess electricity will be used to obtain hydrogen from sea water by means of electrolysis. The hydrogen is then stored in special tanks. At night, the energy facility uses fuel cells to generate electricity, keeping the tower working through the hours of darkness. In the daytime, on the other hand, highly reflective mirrors on the roof direct the sunlight onto a cone of light that goes through the center of the building and provides its various floors with plenty of natural light.

The Burj al-Taqa seems like the most recent example of a trend that has been observable for some time. In large cities such as Chicago, New York or Paris, environmentally friendly skyscrapers are being built that win ecological awards and apparently herald a new green wave in the construction of tall buildings.

But energy expert Mösle is unimpressed by his competitors. "They're constructing buildings that are just as inefficient as their precursors," he says bluntly. "We're not one, but two degrees better than them."

Of course, it is not completely certain that the giant pepper mill in the desert will really turn out to be a wonderful energy source. So far, the engineers have only tested the tower using computer simulations. The investors don't have any tangible proof if the tower actually works either. "They won't be able to check it in advance," Gerber admits.

But he feels confident the investors won't be disappointed. "They have the greatest faith in German engineering," he says.

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