Desert-smart towers carry their own sunscreen
In a city whose skyline is dominated by new and exciting architecture, it takes something special to attract as much attention as the gently tapering Al Bahr Towers.
Standing 145 metres above the junction of Al Saada and Al Salam Street, the landmark twin towers will be the new purpose-built headquarters of the Abu Dhabi Investment Council (ADIC). These 25-storey celebrities have already been named as one of the most innovative buildings in the world, the subject of intense discussion in the architectural press as well as featuring on international radio and TV programmes.
Still under construction, they have already featured on the Chicago-based Council on Tall Buildings and Urban Habitat's "Innovative 20" list of buildings that "challenge the typology of tall buildings in the 21st century". Not bad for a project that is still several months from completion.
Yet all this excitement has largely passed residents by. Even those in the emirate's design and construction industries have been hard-pushed to identify the brooding, dark grey structures that greet drivers as they approach Abu Dhabi's downtown.
Not for much longer. Soon the towers will take their place alongside the Burj Al Arab, Burj Khalifa and Yas Marina Hotel on the list of UAE buildings that command instant and widespread public recognition. Why? Installation has finally started on the building's key structure, a computer-controlled, robotic facade made up of more than 2,000 translucent, parasol-like units that will open and close as the sun moves over their surface. In short, the Al Bahr Towers will be clothed in a moving, protective veil.
The building's architects describe this complex facade as a "dynamic mashrabiya", a 21st century reinterpretation of the carved and perforated screens that traditionally provided shade and privacy to Islamic houses throughout the Middle East. Designed by the engineering firm Arup and architects from the London studio of Aedas, the international practice responsible for Dubai's metro stations and Abu Dhabi's Manarat Al Saadiyat, the building manages to draw deeply on Islamic geometry and heritage for its inspiration while remaining modern and avoiding mimicry or pastiche.
For Peter Oborn, the project director, and deputy chairman of Aedas, the clearest guidance came from the original client brief.
"ADIC wanted a design that would reflect the cultural traditions and architectural heritage of the Middle East, while setting new environmental standards of design," he said.
Mr Oborn and the project's lead designer, Abdulmajid Karanouh, resolved to create a building that was as environmentally friendly and energy efficient as possible, avoiding the mistakes made in generations of buildings throughout the region.
One of the biggest challenges was to achieve all this while meeting the expectations associated with a high-status, high-rise glass tower; a building type thought inimical to sustainable construction given local climatic conditions.
For Mr Karanouh, it was immediately clear that the building required protection from the sun.
"If we were really genuine about creating an environmentally friendly building, we needed to find a way to protect the building from direct sunlight," he said.
Traditional shading devices, however, were not a viable option. "Permanent shading would have compromised visibility and views from inside the building, while lighter shading would have compromised the energy performance of the building itself," he said.
The use of heavily tinted and highly reflective glass, a common practice in the region, was also out of the question. Not only would this distort views from inside the building, it would also increase the need for environmentally costly artificial light.
Mr Karanouh's solution, the dynamic mashrabiya, allowed Aedas to achieve the same kind of performance as a building with a facade that was largely solid. The result is a reduction in the building's overall energy consumption and carbon footprint by 20 per cent while in localised areas on the south side of the tower, which benefit most from the mashrabiya's protective veil, savings are closer to 50 per cent.
The Al Bahr Towers are protected on their east, south and west sides by the mashrabiya. Each of the system's 2,099 units is constructed from 15 components that form a triangular, Teflon-coated, fibreglass mesh set in an aluminium and stainless steel frame. Designed to withstand earthquakes and winds of more than 240 kilometres per hour , some of the units measure 6 metres by 4 metres and weigh almost 600 kilograms. Given their number and size, it is not surprising that the struts that attach the mashrabiya on the facade weigh 240kg each.
With its moving robotic components and complex, computer-controlled solar choreography, the design team had to make sure that the mashrabiya was structurally and mechanically robust enough to withstand the challenges of repeated daily use in Abu Dhabi's challenging climate.
Tests took place at a laboratory in Switzerland, where the mashrabiya units were blasted with sand, dust, and salt water collected from Abu Dhabi and then baked at 60°C to simulate an Emirati summer. Each unit's durability was then tested for 30,000 cycles, the equivalent of doing 75 years' service on the building's facade.
The Al Bahr Towers represent a new generation of building that could rewrite the rule book for sustainable architecture and construction in the Gulf. Mr Karanouh, however, is humbly circumspect. "I consider this building a first step. It is by no means the perfect solution or an ideal solution but it is at least the first step of genuinely trying to make a difference," he said.
While buildings such as the Al Bahr Towers are undoubtedly a step in the right direction, what difference can individual buildings really make to the sustainable development of whole communities?
Abu Dhabi's Urban Planning Council (UPC) is the agency charged with answering that question - and with achieving sustainable development emirate-wide through policies such as Estidama, a programme for the assessment and delivery of sustainable development, and Plan Abu Dhabi 2030.
Michael Stott, a senior associate planner with the UPC, believes that meaningful change will only come from development that has a social and cultural dimension to match economic and environmental imperatives. "This is all part of that wider model of sustainability. Individual buildings are great and can be a showpiece, but we are taking a wider approach," he said. "The future success of Abu Dhabi won't be based on architecture or the public realm in isolation, but on the coming together of the two. If we can put those two together through the development of our policies, we should all have a great place to live."
Not only does the UPC have responsibility for overseeing new development, it also has to address the more challenging issue of retrofitting and revitalising existing communities. Whether it is through the transformation of the parks, streets and public spaces that make Abu Dhabi's public realm, or the assessment and control of new development through Estidama, the ultimate aim of the UPC and the new ADIC headquarters is one and the same, to make life in Abu Dhabi healthier for residents and the environment.
Around the world, the soaring cost of natural gas and wild fluctuations in the price of oil have increased energy prices for consumers, providing powerful incentives for people to monitor and reduce their personal energy consumption. In the UAE, however, the high cost of subsidised water and energy is one of the key drivers behind the government's push for greater sustainability and efficiencies across the board, from individual villas to whole communities. Until widespread metering and greater public awareness of environmental issues shift some of the responsibility for sustainable consumption on to the shoulders of consumers, the responsibility for tangible results will fall to agencies such as the UPC.
It is ultimately for this reason that the organisation places public awareness at the heart of its policy-making and guidance. As Jean Philippe Coulaud, the director of corporate communications for the UPC, explained: "Our key concern is with education. We can speak about policies, technologies, and high-tech devices that we are developing to be more sustainable, but if you don't have all of the community supporting this approach, it won't work."