To enhance environmental performance and create dramatic visual effects, architects devise facades that adapt to changing conditions.
The outer layer of the double-skin facade for the Design Hub at the Royal Melbourne Institute of Technology (RMIT) consists of more than 16,000 individually mounted translucent glass discs repeated on all four elevations of the eight-story main building. The repetition of cellular units has long interested the Design Hub’s Melbourne-based architect, Sean Godsell, an alum of RMIT. In this case, selected groupings of the discs automatically pivot around a vertical axis in response to the sun’s position. This use of a dynamic system represents the latest—and largest—investigation of kinetic technology by Godsell’s eponymous firm, as well as one of the more distinctive examples of the rapidly developing genre of dynamic facades.
- Curtain wall supplier: Permasteelisa Group Pty Ltd
- Exterior shade actuators: D+H
- Curtain wall supplier: Kawneer
- Exterior operable shade supplier: S_enn
- Glazing: PPG Solarban 70XL (typical); PPG Sungate 500 (solar chimney)
- Curtain wall supplier: YKK AP Facade
- Glazing supplier: Shanghai Yaohua Pilkington Glass Group
- Curtain wall supplier: LIXIL Corporation
- Bioskin ceramic tube supplier: Toto
- Glazing supplier: NSG
RMIT Design Hub
Marcella Niehoff School of Nursing and Center for Collaborative Learning at Loyola University
Cooled Conservatories, Bay South, Singapore Gardens by the Bay
Sony Corporation’s Osaki New Building
In past projects, such as a house in Glenburn, Australia, completed in 2007, Godsell has used low-tech devices like metal louvers or gridlike mesh screens to shade glazed facades, an approach adopted by other architects. For the Design Hub, he was asked to pursue a more innovative strategy that would speak to the multidisciplinary design programs planned for the building. “The university was keen to demonstrate its interest in solar technology and green buildings, so we gave them a smart facade that could evolve,” he says.
The outer facade consists of 774 panels, each with 21 sandblasted glass discs, 3/8 inch thick. The panels sit in a steel frame separated by about 3 feet from the building’s inner facade—a more conventional double-glazed, argon-filled curtain wall. In each seven-disc column of the outer skin’s panels, the top three discs are fixed. The bottom four, which are in the occupants’ line of sight, are operable.
The west, east, and north facades, exposed to the harsh Australian sun, contain the movable components. They pivot in waves based on the time of day and year. Over the course of an hour, the discs open as little as 5 degrees up to a maximum angle of 80 degrees. However, their movement, which is controlled by actuators, is so gradual it is hardly noticeable to passersby. The university has the option of one day installing electricity-generating photovoltaics on the discs as part of a technology-development and -testing program.
Dynamic facades, like the one cloaking the Design Hub, are a response to the industry’s latest preoccupation: performance. With architects no longer satisfied to merely decorate a shed, facades have become the primary platform for energy efficiency, thermal comfort, cost savings, branding, and image.
The industry has yet to formally agree on terminology, so it’s easy to find labels like adaptive, transformable, movable, and kinetic applied to these building-envelope systems. But dynamic, in its clear opposition to static, emerges most often as the choice among architects, facade consultants, and manufacturers. “In the most straightforward sense, a building with sensors, controllers for adjustable blinds, and dimmable lighting all tied together is a dynamic system,” says Mic Patterson, director of strategic development for the national facade design-build contractor Enclos. He views projects like the 52-story New York Times Building, designed by Renzo Piano Building Workshop with FXFowle, as essentially dynamic. Even though the veil of 3-inch-diameter ceramic tubes that cloaks the Midtown Manhattan tower is fixed, he points out, the curtain wall, manufactured by Portland, Oregon–based Benson Global, is integrated with other building systems, such as lighting and interior shades, to affect solar-heat gain, daylighting, glare, thermal comfort, and, ultimately, energy performance.
The conventional wisdom regarding dynamic building envelopes is that they are costly, require burdensome ongoing maintenance, and are best suited to a Northern European climate. Such industry challenges did not deter architects at Solomon Cordwell Buenz (SCB) from proposing a dynamic facade for the Richard J. Klarchek Information Commons, completed in 2007 at Loyola University in Chicago. SCB’s ultimate success with that building’s double-skin, fully glazed curtain wall, automatic venetian blinds, and operable windows laid the groundwork for a series of recent projects for the university that deploy similar strategies, resulting in significant energy savings and highly transparent, comfortable facilities that have been a hit with Loyola’s students, faculty, and administration.
Devon Patterson, the principal at SCB who has led the design effort for Loyola (no relation to Mic Patterson), built on his experience with the information commons to implement a natural-ventilation strategy for the university’s Marcella Niehoff School of Nursing and Center for Collaborative Learning, a 60,000-square-foot, four-story classroom and office building opened in August 2012 at the medical school’s campus in Maywood, Illinois. Working with a team that was almost identical to that on the earlier Loyola project—local mechanical firm KJWW Engineering Consultants, the New York office of the German energy-efficiency consultant Transsolar, and Enclos—the architects devised two glazed solar chimneys for the nursing-school building’s south elevation. These bookend a glazed facade with fixed shading louvers. The chimneys feature double glazing with a low-emissivity coating and a relatively high solar-heat-gain coefficient (SHGC) of 0.62. (SHGC, expressed as a number between 0 and 1, measures the solar radiation transmitted through a glazed unit. The lower the number, the less radiation transmitted.) In contrast, the building’s typical vision glass, enclosing spaces where heat gain is less desirable, has an SHGC of 0.25.
During the so-called shoulder seasons of the spring and fall, automated windows on the north facade open to provide cross-ventilation to the building’s public spaces and offices. The air, assisted by a combination of the stack effect and external pressure differences, exits the building through the solar chimneys. In the winter, the operation of the chimneys is reversed, with air-handling units in the basement drawing fresh air from louvers at the roof. Solar gain along the glazed chimneys preheats the fresh air before it is distributed throughout the building. The strategy results in a 40 percent improvement over the ASHRAE 90.1-2007 energy standard and an energy-use intensity (EUI) of 43 kBtu/square foot (EUI is a standard way to gauge the annual energy consumption of a building relative to its size). Typical academic buildings have EUIs well above 50.
Erik Olsen, the managing director of Transsolar’s New York office, says that shading devices, as well as dehumidification, are critical for the proper function of a natural-ventilation scheme—especially in Chicago, with its hot and humid summers. The nursing school’s east facade abuts another structure, but the triple-glazed west elevation features automated external blinds. These are made of stainless steel blades approximately 1/8 inch square in section with 1/16-inch gaps between them—an interval that allows daylight to be reflected into the building off the top surface of each blade, while reducing radiant-heat gain by 90 percent. Without these operable shading elements or the south facade’s fixed shading louvers, the building would have needed a much larger HVAC system, says Olsen.
Transsolar also advised on the design criteria that informed the 133-acre Gardens by the Bay project in Singapore, designed by Bath, England–based landscape architects Grant Associates and London-based Wilkinson Eyre Architects and opened in June 2012. Unlike the Loyola buildings, which are focused on human comfort and energy efficiency, the Singapore project sought to maintain optimum daylight levels for the plants housed in two gridshell- and arch-supported glazed conservatories enclosing over 200,000 square feet. The architects needed to achieve approximately 4,200 foot-candles of sunlight without overheating the interior of the bulbous structures, which, from some angles, look like humpback whales surfacing in the ocean.
Singapore has a hot, humid climate with ample sunshine, but it is also cloudy and rainy for a large portion of the year. The envelope had to adapt to these changing conditions to maintain daylight levels and minimize heat gain. The design team investigated several options, including balloons tethered overhead and venetian blinds, but finally settled on external shades because they could be more easily integrated and automated, according to Matthew Potter, a Wilkinson Eyre associate director. “We also wanted the shades to have some spectacle,” he adds, describing the fractal pattern of the deployed shades as similar to the surface of a pinecone or pineapple.
The shades are controlled by sensors that monitor light levels, as well as temperature and humidity, throughout the interior landscapes. When light levels increase beyond acceptable thresholds, motors automatically unfurl triangular pieces of tightly woven canvas rolled up and concealed within the buildings’ structural components. The shades unroll from one arch, pulled in an almost continuous loop configuration by a cable that spools on a rod concealed in the opposite arch. As they are pulled across the double-glazed envelope, the shades visually interlock but allow some light transmission even when fully extended.
The movement of dynamic envelope systems isn’t always as dramatic as at Gardens by the Bay. Sometimes a facade’s operation is almost completely invisible, as it is at an office building designed by architects and engineers at Nikken Sekkei for Sony in Tokyo and completed in 2011. The 25-story, 1.3 million-square-foot structure, which the corporation recently sold as part of a reorganization of its assets, features a “bioskin” inspired by unglazed ceramic water jugs seen throughout Southeast Asia. As water evaporates through the porous walls of these traditional containers, it helps keep the drinking water inside cool on hot days, explains Tomohiko Yamanashi, chief architect on the project. With that in mind, he and his Nikken engineering colleagues developed the steel-cable-framed structure that hangs approximately 7 feet off the exterior of the Sony building’s double-glazed curtain-wall facade. The resulting cavity forms balconies for every floor, and the cable frame supports a series of horizontal ceramic pipes reminiscent of traditional Japanese bamboo-and-string curtains. Rainwater captured from the building’s roof circulates within these porous elements.
Yamanashi’s original hypothesis assumed that the evaporative cooling of the pipes, which are approximately 3 inches tall and 4 inches wide in section, would reduce solar gain on the building, resulting in improved energy performance. Nikken Sekkei extensively mocked up the facade, collaborating with toilet manufacturer Toto on the design of the ceramic pipes.
Simulation work carried out by the University of Tokyo predicted a reduction in surface temperature of the external facade layer, but not enough to warrant installation of a smaller mechanical-cooling system. However, the researchers discovered an unexpected benefit of the bioskin—the studies indicated that the facade would reduce ambient air temperatures in pedestrian areas surrounding the building by 2 degrees Fahrenheit. Yamanashi contends that the research was too conservative, but he is pleased that the system helps mitigate the urban-heat-island effect. “We tend to think of green architecture selfishly, as in having better energy efficiency for only our building,” he says. “But the Sony building is more altruistic, and the bioskin can improve Tokyo’s concrete jungle.”
Subsequent monitoring has confirmed that ambient air temperatures at the building’s ground level are consistently 3 degrees Fahrenheit lower than the rest of the neighborhood. Although the project didn’t achieve its original ambitions, Yamanashi considers such experimentation with dynamic facades critical. Investigation is necessary for gaining a better understanding of the most effective ways of reducing buildings’ environmental footprint, he says. It’s a point on which many of his peers in architecture agree.
Russell Fortmeyer is a Los Angeles–based engineer and journalist. His book Kinetic Architecture: Designs for Active Envelopes, written with Charles Linn, is due in July from Images Publishing.