Though some firms would be content to design a typical rectangular tower and call it a day, that's really not BIG's style, and the firm once again offers a unique twist on skyscraper design with its Shenzhen Energy Mansion. The recently-completed project consists of two towers that reduce solar glare and energy requirements with their undulating form and stunning pleated facades.

The Shenzhen Energy Mansion, which also involved Transsolar and Arup, was commissioned following an architecture competition in 2009, and its construction began in 2012. Its two towers rise to 120 m (393ft)-tall and 220 m (721 ft), respectively. They are joined together by a 34 m (111 ft)-tall podium that contains lobbies, a conference center, cafeteria, and an exhibition space.

Inside, the buildings have a combined floorspace of 96,000 sq m (roughly a million sq ft), with the upper floors reserved for the Chinese state-owned Shenzhen Energy Company, and lower floors offering rented office space. The protruded section of the taller skyscraper hosts meeting rooms, executive clubs, and staff facilities.

The buildings' facades comprise glazing and an aluminum skin which is patterned to control the amount of daylight that permeates within. This, along with strategically situated folds, helps mitigate the sun's glare and solar heat gain, thus reducing energy requirements for air-conditioning and other cooling methods.

"By folding parts of the envelope that would reduce solar loads and glare, a facade with closed and open parts oscillate between transparency to one side and opacity to the other," says the firm. "The closed parts provide high-insulation while blocking direct sunlight and providing views out. As a result, the towers appear as a classical shape with an organic pattern from a distance and as an elegant pleated structure from close-up.

"The sinuous direction of the facade corresponds to the solar orientation: it maximizes north-facing opening for natural light and views, while minimizing exposure on the sunny sides. This sustainable facade system reduces the overall energy consumption of the building without any moving parts or complicated technology."

The Shenzhen Energy Mansion has been awarded LEED Gold certification (a green building standard). Other sustainable features include efficient lighting systems, greywater recycling, and each building is topped by a green roof.

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