January 2019 - Many architects and designers might be said to hone their visions by taking into account three Ps: Perspectives, possibilities and performance. When these three ideas come together, it should result in a building that is pleasing and even inspirational, particularly if the finished work caters to students.

When Morphosis Architects in New York was chosen to design the Emma and Georgina Bloomberg Center at Cornell Tech, efficient heating and cooling as well as beauty had to be considered.

Often, architects will specify rainscreen systems for the façade to fulfill two primary functions: the first is to keep moisture from entering a building; the second is to prevent heat from escaping. Thanks to a collaboration between Morphosis Architects, engineering and fabrication firm A. Zahner Co. and PPG, the rainscreen system on the Bloomberg Center at Cornell Tech does more than serve those purposes; it also works as a color-shifting wall of art.

Set on New York City’s Roosevelt Island, the Bloomberg Center is the first academic building on the new Cornell Tech campus. The school itself represents a partnership of Cornell University in upstate New York and the Technion-Israel Institute of Technology. Morphosis designed the 160,000-square-foot structure to be the intellectual nerve center of the campus, with classrooms, instructional labs, conference rooms, a lecture hall, cafe and other shared spaces.

The Bloomberg Center at Cornell Tech features a solar roof and perforated panels in a copper brown patina from PPG.

The center also was planned with the goals of melding environmental sustainability with leading-edge design to achieve net-zero energy use and Leadership in Energy and Environmental Design (LEED) certification at the Platinum level. (LEED is the most widely used green building rating system in the world.)

The most visible expression of those objectives is the exterior layer of the rainscreen, an aluminum panel system that envelopes the four-story building to reduce its cooling load, while serving as a visual tether for its floating 40,000-square-foot solar canopy.

Featuring iridescent, color-shifting PPG Duranar Vari-Cool coatings, the panels were designed by Morphosis with A. Zahner Co. fabricating a façade that harmonizes with the local landscape.

Pixels and perforations

Zahner finished the panels with PPG’s iridescent coating. Then, using its proprietary Louvered Zira system, the company perforated 337,500 2-inch circular tabs across the exterior surface of the rainscreen.

Because the perforations are individually programmed to reflect a specific volume of light, they act like pixels that, when viewed from afar, produce a continuous image depicting Manhattan’s skyline on the west façade and the famous gorges of Ithaca, New York on the east façade.

Formulated with a 70-percent polyvinylidene fluoride (PVDF) resin, PPG Duranar Vari-Cool coating combines pearlescent pigments that change color according to ambient lighting conditions, with PPG’s Ultracool infrared-reflective coatings technology, which deflects solar heat away from buildings to keep them cooler.

While the Bloomberg Center design team chose these coating technologies in part to manage vapor and heat barriers, the ability to shift color made it the product of choice for this project.

“We were interested in [creating] a dynamic building that changes under different light conditions during different seasons and from different perspectives,” says Ung-Joo Scott Lee, a principal with Morphosis and project leader for the Bloomberg Center. “We had never used the Vari-Cool product before, but we are always interested in exploring new materials and finishes.”

After reviewing numerous colors, the design team selected copper brown patina for its wide-ranging brown to greenish-blue hue.

“The brown tone provides an industrial machine-finish quality that is similar to the Queensboro bridge nearby,” Lee explained. “The bluish-green hue is the color of the East River and the Cornell Tech landscape. Together, they very literally marry the building to its new Roosevelt Island campus in New York City.”

Precoat Metals has 14 coil coating facilities across North America. The Jackson, Mississippi, plant painted the coils for The Bloomberg Center.

Involving students

The digital patterning of the perforations was created by running the rainscreen panels through a repurposed welding robot. Students from Cornell Tech and the Massachusetts Institute of Technology collaborated with Zahner to develop the algorithm that controlled the device, which made them major contributors to the façade design.

Lee says the students’ involvement was deliberate and strategic. “We had been working with Zahner for several years because they share our design interests and curiosity, with meticulous care for detail and constructability,” he adds. “The students were engaged because they are talented, but also to emphasize the type of connections that Cornell Tech will foster between academia and the tech industries.”

Corrosion resistance

Scott Moffatt, PPG market manager, architectural coil and extrusion coatings, worked with Zahner to make sure the coating would meet the long-term performance challenges associated with the building’s riverside setting.

“Zahner contacted us because they planned to laser-cut the perforations into the panels after the coating had been applied, and they were concerned about disrupting the paint finish,” Moffatt says. “They sent us a few sample panels and we ran the corrosion tests. The results were positive, so everything was approved.”

The façade also incorporates cut-aways to accommodate wide bands of high-performance glass, enabling it to achieve the recommended 60:40 wall-to-window ratio for balancing opacity, outdoor views and transmitting natural light indoors.

Designed as one of the country’s largest net-zero-energy academic buildings, the Bloomberg Center features smart building technologies; geothermal wells with ground-source heat pumps for heating and cooling; a 40,000-gallon rainwater harvesting system; and a green roof planted with native species.

These strategies, together with the solar paneled canopy, are expected to help the building generate as much energy as it consumes.

Holds promise

The coil coater for the project was Precoat Metals. Precoat plays an important role in the process by combining the decorative and functional properties of the coatings with the strength and durability of the metal coils, according to Stephen F. Johnson, director of marketing and planning. “Due to the complex nature of metal supply chains, it is sometimes difficult to trace where the material ends up,” he says, “but in this case we know the Bloomberg Center façade’s material was coated at Precoat’s Jackson, Mississippi, facility.”

Each of the company’s 14 facilities able to apply the Vari-Cool coating. “Our experience with it has been very positive.”

Precoat Metals recently introduced four brand families to better communicate the types of products it applies. “Because the PPG Vari-Cool system offers dimensionality through its ability to change colors depending on viewing or light source angle, it fits within our PCM Dimensions family of products,” Johnson explains.

“We have received excellent feedback from those specifying Vari-Cool coatings. While it is a premium system, it is still a very cost-effective solution that offers a high level of visual interest,” he says. MM