Penn's Vagelos Laboratory for Energy Science and Technology: The Green Gateway

The intersection of Walnut and 32nd Streets is a prominent entry point to the University of Pennsylvania's West Philadelphia neighborhood as a visitor approaches from the Walnut Street Bridge across the Schuylkill River. Along with Penn's athletic facilities to the immediate south (including the 1927-vintage “cathedral of college basketball,” the Palestra), the building currently taking shape on the southwest corner will help shape first impressions of the university. The Vagelos Laboratory for Energy Science and Technology (VLEST), a 111,000-square-foot facility with a multi-cantilever profile and a facade foregrounding its solar-control system, will visibly announce its purpose and, by implication, an important component of Penn's: This institution serves a future where the climate emergency is a central priority.

Robert Matthew Noblett, project architect and partner at the Boston office of Behnisch Architekten, says the VLEST “needed to be a statement building, an icon of sorts, something that spoke not only to Penn's presence that far east—it's almost at the river—but as well to the energy mission of the building.” The Vagelos Institute for Energy Science and Technology has existed since 2016 as an umbrella research institute headed by chemist Karen I. Goldberg and comprising faculty from the School of Arts and Sciences (SAS) and the School of Engineering and Applied Science (SEAS), which jointly operate the undergraduate dual-degree Vagelos Integrated Program in Energy Research, also slated to occupy the new building when it opens in September 2024.

“It's a lab building almost 100 percent,” Noblett says, where researchers will collaborate on “studying the potential for methane to be converted into a usable fuel” along with battery technology, renewable use of nonfood biomass, and other aspects of both basic and applied research advancing the transition to sustainable energy sources. “They're all looking for solutions to an energy problem that is more than emerging,” he notes; “it's upon us.”

Designing a seven-story building to be conducive to collaborative work, Noblett says, particularly on a compact site, involved close attention to vertical circulation, both for emergency egress and for “either visually or physically communicating with one another” on different laboratory floors. (Many people will typically take stairs three flights up or three down, he notes, “but after that it's an elevator building,” a condition the team strives to avoid here.) Behnisch wanted to “avoid the cost and the technical complications of one big atrium space that has lots of stairs flowing in it, so this has actually a series of two-story spaces that switch back and forth between the north and south parts of the building.” The double-height spaces, staircases, and hallways orchestrate circulation among the labs, faculty, offices, and meeting rooms (see Image 12). “Any time that you carve big openings in a floorplate, it gives our structural engineers a little bit of heartache,” he adds, “but most of that is doable and knowable at this point.”

Photo courtesy of Behnisch Architekten

Image 12: Vagelos Laboratory, University of Pennsylvania, in north-south section.

Photo courtesy of Behnisch Architekten

Image 13: Vagelos Laboratory, eastern elevation from Walnut Street overpass at 32nd Street.

The structural system in a lab building has to control vibration and protect sensitive equipment. SEAS optical researchers, Noblett points out, “have air tables that deal with a certain amount of the vibration, but everybody in the building wants to know that they have a good solid basis for their equipment and for taking measurements. So that automatically tends to exclude wood, even mass timber, as a viable option, because it's too light and doesn't provide the stability, and then you're left with a decision about steel or concrete. And so in our case, we opted to design this as a steel building.”

The choice over concrete was clear on several grounds: not only comparative carbon footprints consistently favoring steel, Noblett says, pointing to a Guardian report on the environmental impacts of concrete (Vidal), and cost amid East Coast market fluctuations, but declining expertise in concrete construction. “In the '60s and '70s, that was a very popular building material,” he says, “but the knowledge base has started to decline; I think there [are] fewer people who know how to really do a concrete building well, and it's tended to drive the cost of that up, so in our experience... we're a steel industry now.” Concrete has “benefits, certainly, in terms of providing thermal mass and taking the peaks off of the thermal performance of the building, but it's very hard to ignore that penalty you pay in terms of carbon emissions related to concrete. So steel can be very carbon-intensive, but the recycled content that we're able to achieve now with a pretty standard specification makes it really very competitive in that regard as well....Until lower-carbon concrete alternatives become viable in the market in terms of scaling cost, I think we're going to see less and less; certainly in our practice, we'll do as little concrete as we can, with that in mind.”

The VLEST's laboratories and public spaces use acoustical steel decking, Noblett says: a fluted product inserted with a perforated cover on top of the steel frame, filled with acoustical insulation. “It is a little bit more expensive” than alternatives, he allows, but “especially in buildings with multi-story openings and a good amount of glass as well for daylight penetration and visual communication, we need something to absorb all that acoustical energy.”

Sunshades made of ethylene tetrafluoroethylene (ETFE) cover the VLEST's facade like the scales of an armadillo. In “a ventilation-intensive lab building,” he continues, “the cooling loads tend to drive the system design, so the less heat energy we can apply to the inside, the better.... What felt right to us architecturally was something that operated at the scale of the floor-to-floor height of the building [15'6”], and then that immediately starts to bring into the question what kind of materials can span that distance safely and in terms of structural performance, but also be as light as possible and impose the lightest amount of load on the building superstructure.” The ETFE film stretched over a steel frame includes two components, an upper segment resembling frosted glass diffusing light over the clerestory windows and a more opaque ceramic-fritted lower portion shading the vision glass.

Photo courtesy of Behnisch Architekten

Image 14: Courtyard formed by Vagelos Laboratory’s west facade and Rittenhouse Laboratories (background).

Photo courtesy of Behnisch Architekten

Image 15: Floor plan, Level 1 of Vagelos Laboratory, with Rittenhouse Laboratories to left (west) and Palestra below (south).

The VLEST sits on a robust mat foundation, needing no deep foundation work; still, its site poses three-dimensional design and engineering challenges. As a “theoretical intersection” where 32nd Street passes one full building level below the elevated Walnut Street, with a commuter train line running underneath parallel to 32nd and the building meeting an abutment that supports Walnut, the location involves “not only vibration, but electromagnetic interference,” Noblett says. “It's a funny site: before it was a building site, it and the corresponding courtyard were just a parking lot for David Rittenhouse Laboratories, which is the adjacent building.” The Palestra has “a significant portion of their egressing going through the northern doors of their building” directly south of the VLEST. To not only avoid interfering with sports crowds but actually improve their views, Behnisch bends the VLEST from orthogonality to Walnut to a tipped-back form at a line from the corner of the Palestra to a point on the eastern facade, so that the VLEST “opens up and exposes that eastern elevation of the Palestra,” whose north facade becomes the fourth wall of a new courtyard (see Images 14 and 15). “There's a very public and campus-centric approach to what we consider the ground plane, which is Walnut Street.” Below that plane at 32nd Street are a loading dock, certain high-performance labs, and building technical systems. “There's almost an infrastructural investment in that elevation to tie together some parts of the campus that have been heretofore been a little bit disparate and not so pleasant.”

Connected to a campus energy system, the VLEST takes pains to avoid the energy-hogging often found in lab buildings. “There's an old approach to labs which says, 'Ventilate them as highly as possible, and don't worry about what's going on in there, because no matter what, it'll be safe,’” Noblett says. “It turns out it's terrible for the energy performance of a lab building, and it's also not all that safe, either, because if you don't know what's going on there, you're not really being safe, no matter how much are you're pumping through.” The building uses a heat-pump chiller that draws heat energy from the campus loop and returns chilled water to the central plant, plus a highly efficient Swiss convective heat-recovery system on the roof. “This is a device that's existed since the '50s in building technology...basically, convective has taken the old glycol runaround heat exchanger and turbocharged it. It's actually a very big device, and it's a very big coil, and it has very smart software that optimizes the heat recovery, so if a typical system of that nature would have an efficiency of around 40 percent to 50 percent, historically, this is achieving efficiencies of up to 85 percent to 90 percent. So between the ventilation rates and the heat recovery, we make a huge dent in the energy profile of the building.”

Penn has recently announced a partnership with a massive solar array in central Pennsylvania, breaking ground in 2022 for a system projected to provide 75 percent of the campus's electricity, advancing toward the university's goal of fully carbon-neutral operations by 2042. Noblett observes that this effort “responds to a huge outcry from student populations for exactly the kind of research that's happening here, and also for buildings that reflect the ethos of planetary stewardship.”