GALLERY | Shenzhen’s ‘breathing’ office building
With a distinctive diagrid structure and an atrium that functions as “lungs” for the office, the 33-storey Shenzhen Rural Commercial Bank HQ is a model for healthy buildings in a post-pandemic world.
At a glance
- Location: Shenzhen, China
- Height: 158m
- Size: 94,000 sq m
- Architect: Skidmore, Owings & Merrill
- Sustainability credentials: LEED Platinum
- Completion: 2020
Central to the building’s design is the atrium to the east and west of the building. Acting as the tower’s lungs, they naturally ventilate the tower on days with good outdoor air quality.
Luke Leung, principal at SOM, says: “Using the natural forces of the tower, the atria drive return air upwards from each floor to the mechanical floors for filtering and recirculation. This system naturally and efficiently moves air throughout the building.”
He says that the naturally ventilated spaces can generate energy savings of up to 12% compared to a traditional HVAC system, though mechanical air conditioning is still required.
Meanwhile, the tower uses smart fan coil units with electronically communicated motors, which reduces monthly energy consumption by 19% while taking up less space within the core.
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On each floor of the tower, employees can use louvres to open and close vents and let fresh air into the atria.
Leung says: “The idea of adaptive comfort requires users to have the perception of control in their environment, including the ability to open the window or not. Even a simple gesture like this allows users to control their comfort levels, and operable windows are common in traditional Chinese buildings, so many users are familiar with them.
“When windows are opened, occupants tend to accept a wider range of thermal comfort parameters than a typical air-conditioned environment.”
The external diagrid has two main functions: to provide shading and to create an entirely column-free floor plan.
Shading reduced solar gain by about 34%, crucial for the region’s tropical weather, and reduced the surface temperature of the exterior glazing. This lowered the mean radiant temperature in the building, thereby creating a more pleasant environment to work in.
Meanwhile, having no columns increased the efficiency of the office layout. Leung says: “A structural analysis calibrated the diagrid to accommodate different structural loads for the building, so the resulting amount of material is incredibly precise and minimises resource usage.”
That optimisation cut the amount of steel needed in the tower by 15%.
Multi-storey water wall
Another feature that adds to the building’s thermal comfort is a 15-metre high rain curtain in the lobby. Water cascades down glass walls, cooling the space and tying it into the design’s overarching themes.
Leung says: “An ‘earth to sky’ approach was the guiding design philosophy. The lobby emphasises earth elements: stone, water, air, greenery. Upper floors represent sky: crisp, airy, open and emphasising the airflow.
“In the wake of a pandemic, natural ventilation is a growing need in contemporary buildings to promote the health and wellbeing of occupants. This project advances the structural skillset available to contemporary buildings moving forward. The ability to integrate these features with nature to a higher degree will set the tone for future projects.”