The 20th and 21st centuries are dotted with iconic skyscrapers by the architecture and engineering firm Skidmore, Owings & Merrill (SOM). The Hancock Tower, the Willis Tower (formerly Sears Tower), the Burj Khalifa, and the still-under-construction One World Trade Center all soar heavenwards as feats of design and engineering. And some 40 years into designing super-tall structures, the firm is continuing to innovate. Its Digital Media City Landmark Tower in southwestern Seoul, South Korea, brings sustainable design skyward.
At 2,100 feet tall (133 stories), the mixed-use tower hosts a collection of green technologies, including solar panels, wind turbines, enhanced daylighting, and living walls. SOM anticipates that these strategies will reduce overall building energy use by 66 percent. “Original constraints on super-tall buildings were vertical transportation and structural requirements,” explains SOM design partner Mustafa Abadan. “Today, those requirements have become easier to solve with technological advancements, but sustainability needs to be addressed. We’ve shifted our priorities to environmental issues.”
Located on a 37,208-square-meter (401,278-square-foot) site west of downtown Seoul and north of the Han River, in an area slated for development as a technology and media hub, the super high-rise is designed to be a beacon for the region—literally. LED lights integrated into the façade will be programmed to correspond to sky color and come on at sunset, creating a dynamic light display.
Yet the building’s environmental responsiveness is not just for show. The tower promotes urban density. A micro-city in itself, its mixed-use program includes an eight-story retail podium, 39 office floors, a 16-floor hotel with a double-height lobby, 19 serviced apartment floors, 39 residential floors, one restaurant floor, three observation decks, and eight mechanical floors. One of Seoul’s major train stations is within walking distance.
Despite the symbolic display, the tower’s spectacle comes in its forward-thinking production of renewable energy. SOM’s team reconfigured the standard super-tall building footprint, where the core is usually taken up with structural supports and vertical transportation. About halfway up the buildingat the hotel lobbythe more-traditional core is replaced by a 1,000-foot-tall vertical void. Roughly 60 feet wide by 100 feet long, the void is based on the principles of a solar updraft tower. Using the stack effect, air will be drawn into a collection area, where it will be heated naturally by the sun before it rises up through the tower to drive six horizontal-axis wind turbines, each 3 meters (about 10 feet) in diameter. SOM predicts that this “solar engine” will provide 3 to 5 percent of the building’s overall energy. “Tall buildings naturally act as chimneys,” Abadan explains. “There is a natural draw of air that, up until now, we’ve had to fight. In this tower we’ve embraced this phenomenon. Super-tall towers have always been designed around structural concerns, but we’ve also recognized that other forces acting on the building can be harnessed in a different way.” Additionally, there are plans to capture methane from an adjacent landfill and convert it to fuel. Nicholas Holt, a director at SOM, projects that the gas given off from decomposing trash combined with wind turbines installed on land south of the site could supply 20 percent of the entire building’s power.
Integrated systems are key to maintaining an efficient super-tall building. For example, the structure’s electrical and mechanical systems are optimized with high-efficiency lighting fixtures, chilled beam cooling in the office spaces, and radiant flooring in all residential and hotel guest room spaces. The exterior façade is designed to generate both shade and energy. The southern façade will be outfitted with horizontal shading fins, while the eastern and western façades will have a combination of horizontal and vertical fins. Discussions are under way to install photovoltaic (PV) panels on a to-be-determined mix of fins on all three sides. It is anticipated that the PV panels will be installed on the lower portion of the building for easy maintenance and will generate 1,400 mWh of energy to be fed back into the site or sold back to the grid. Around the central atrium, glass panels will allow natural light to filter deep into the floor plates.
SOM’s ability to stay on the cutting edge of performance technologies comes from in-house research and advanced computational power. By using a combination of software packages, the team is able to empirically model complex environmental systems such as heat gain, solar incidence, and thermal dynamics. In fact, prototypical development done in partnership with the Center for Architecture, Science, and Ecology (CASE), which is a research entity co-hosted by SOM New York and the Rensselaer Polytechnic Institute, led to the tower’s “lungs.” CASE had designed an Active Modular Phytoremediation System (which won a 2009 R+D Award from magazine) and, for the tower, collaborated with SOM to improve existing green wall technology. Up to 90,000 square feet have been allocated within two U-shaped perimeter voidsone on the building’s north side, one on the southto house green walls. Each void will be broken into three stacked segments and in the upper segments of each U, the green walls will cleanse air by drawing it across the plant leaves, roots, and rhizomes, which together filter out VOCs and toxins. The walls also will pre-cool the air, reducing the amount of energy needed to cool the apartments. Grown hydroponically, the green walls will be supported by the building’s graywater reclamation system.
Although the Digital Media City Landmark Tower is just out of schematic design and completion is anticipated in 2014, it represents the future of super-tall architecture. “We’ve incorporated a level of environmental enhancement that goes beyond what has been thought of up until now,” Abadan says. No longer will it be enough to race upwards solely on feats of structural engineering, it’s now sustainability’s turn to scrape the sky.
Mimi Zeiger writes about architecture from Brooklyn, N.Y.
