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Metropolis Editors, Natural Habitat, sustainability, sustainable architecture

METROPOLIS Introduces Natural Habitat, a Sustainable Homes Video Series

The series debuts with a tour of a tranquil upstate New York retreat designed with Passive House principles.

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December 17, 2021

A SOM-Designed Bank in China Provides Fresh Air During Mild Months

The new Shenzhen Rural Commercial Bank Headquarters is an example of a rare tall building designed to be naturally ventilated.

By: Russell Fortmeyer

Photography: Seth Powers

The SOM-designed Shenzhen Rural Commercial Bank Headquarters, in Shenzhen, China, joins an exclusive club in architecture: that rare tall building designed to be naturally ventilated. To achieve that feat, the nearly 500-foot-tall, 33-story building integrates several environmental strategies into a dynamic envelope and diagrid structural system.

“We took a mixed-mode, multiseason approach to the design,” says Scott Duncan, SOM design partner. Providing fresh air during Shenzhen’s more pleasant months, the strategy saves nearly 10 percent in annual energy costs, Duncan notes. 

building exterior showing exposed structure
The tower’s steel diagrid structure, visible inside and out, generates expansive, column-free interior spaces. The white-hued frame also provides solar shading, reducing solar gain by more than 30 percent.

Atria on the east and west sides of the building extend its core zone to the perimeter, effectively splitting the tower in two. Incorporating open stairwells,  these atria run vertically through the entire height of the tower, providing—via natural air circulation, automated louvers, and mechanized window vents—fresh air into and out of the structure. (Return air louvers inconspicuously incorporated into the atria walls are always open and provide a direct air path to exhaust.) During Shenzhen’s hot, humid summers, a conventional chiller plant in the basement provides cold water to fan-coil units in the building’s open office ceilings when needed. It’s a flexible system that allows some tenants to use mechanical conditioning while letting others rely on natural ventilation. 

The building’s steel diagrid structure creates a uniform lattice across the entire facade, minimizing its framework and creating column-free interior spaces. Chuck Besjak, SOM’s structural engineer for the project, says the diagrid is nearly 15 percent more efficient than a conventional tower frame. Clad in white panels to provide a consistent aesthetic, the diagrid plays multiple roles. Primarily, it addresses gravity and lateral loads for the building, tying back to the concrete core on every other floor with a ring truss. Secondarily, it acts as a solar shade, reducing heat gain by an average of 35 percent on the envelope and thereby expanding the seasonal effectiveness of natural ventilation. 

Shenzhen’s outdoor air quality is a concern at times, but the building’s control system monitors particulate and VOC levels for indoor air and adjusts between ventilation modes accordingly. 

  • lobby interior showing entrance and interior plantings
  • people in multi use space in front of atrium window
  • view of side atrium that extends all the way up the building, promoting air flow.
    East and west atria run vertically through the height of the building, allowing fresh air in and out via a system that includes natural air circulation, mechanized window vents, and automated louvers.

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