Harvard University’s new building features hydroformed facade for energy efficiency
by arslan_ahmed | May 2, 2023 1:33 pm
Harvard University Science and Engineering Complex (SEC) in Boston, Massachusetts, uses a specially designed hydroformed tensile facade system made of stainless steel to maximize energy efficiency and provide occupant comfort.
The eight-story building spans across 50,539 m² (544,000 sf) and is organized into three four-story volumes connected by two glazed, multi-story atria, which provide light-filled social hubs for faculty and students. Classrooms, makerspaces, teaching labs, and amenity spaces occupy the floors closer to the street, to highlight active learning, showcase student work, and engage the community.
Wet and dry research labs are in the upper volumes, where they provide researchers with more solitude and security. Modular, flexible laboratory environments, smart zoning of highly ventilated zones from dry spaces, and robust delivery of centralized lab services ensure the adaptability of the space for decades to come. Between the laboratory blocks, generous lounges provide connection points for students and faculty.
Collaborating with the structural engineering firm, Knippers Helbig, Boston-based architect, Behnisch Architekten, designed a sophisticated screen enclosure made from a hydroformed tensile facade system for the research areas on the upper floors. The facade’s stainless-steel material is both delicate and lightweight, mimicking the qualities of fabric. The fixed sunshade screen is designed to reduce peak cooling loads by 65 percent, while directing daylight deep into the interior spaces.
The panels, made from 1.5-mm (0.06-in.) thick stainless steel, are fabricated using the hydroforming method, common in the industrial and automotive industries. After folding to achieve structural integrity, the edges were perforated using laser cutting, blurring the contrast between shade and exterior. The minimal tensile support structure of the panels allows views and daylight to penetrate into the interiors. The panel cassette is bolted directly to spring-tensioned vertical steel rods, with only wind bracing at the spandrel levels.
Depending on its exact position on the facade, each screen is precisely dimensioned and machined to shield the building interior from solar heat gain during warmer months, while it lets beneficial sun in during the winter. This significantly reduces cooling and heating loads on the mechanical plant.
The thermal enclosure behind the screen is triple-glazed and punctuated with operable windows to facilitate natural ventilation of the building’s interior.
Josef Gartner GmbH, a division of Permasteelisa North America Corp., faced the challenge of producing 12,000 precisely milled panels in 14 different shapes, requiring innovative fabrication techniques. The team was inspired by utilitarian objects, such as soup cans, wheelbarrows, and car bodies, and used advanced software, such as computer aided three-dimensional interactive application (CATIA), to optimize the screen panels for strength, production, and visual qualities.
There are three other facades used in the building to meet sustainability goals. The lower two floors and all the south-facing portions of the building feature highly transparent, one-story glass ribbon windows that span floor to ceiling. Every two out of three modules of the unitized aluminum system are fully glazed; the third module is opaque. Operable windows are integrated into every third unit.
Another facade system, a triple-glazed, double-height, steel-framed configuration, produces a clean interior appearance and is installed on multi-story spaces at major building entrances. Operable flaps at the upper levels of this facade support automated natural ventilation.
The third facade system is built over the six-story wall of the main atrium; which is approximately 22-m (75-ft) wide and 19 m (65 ft) high; and the three-story wall of the west atrium, measuring about 13 m (45 ft) wide and 16 m (55 ft) high.
The challenge of integrating the structural requirements of these long-span glass walls with the exterior sunshade—required to maintain thermal comfort in the atria spaces—is met with a custom shading element that also acts as a rigid wind collector beam. Both the shading system and the triple-glazed wall behind it are suspended from the overhead roof structure.
Some of the other ways in which the project achieves sustainability are as follows:
- Extensive plantings at varying levels of maturity populate the landscape, including native species, as well as specimen samples informed by the holdings of Harvard’s Arnold Arboretum, connecting the project to the university’s history.
- The ground floor of the building and the perimeter landscape are situated safely above the 100-year flood level. A 90-m (300-ft)-long bioswale facilitates filtration by channeling rainwater to three below-grade storage tanks; the tanks’ capacity allows for 100 percent containment of a 100-year storm.
- Precisely defined proper and safe minimum air flows, laboratory ventilation management planning, and high-efficiency heat recovery are priorities of the building systems planning. To reduce energy use—a significant challenge in a lab building—the architect concentrated on driving down ventilation air flows and building thermodynamics.
- Consuming as little as one-third the energy of comparable air-driven systems, hydronic heating and cooling systems provide efficient, silent, and draft-free tempering of the SEC’s interior. Concrete slabs embedded with fluid-filled tubing provide radiant heating and cooling; the mass of the warm or cool slabs stabilizes internal temperatures year-round. User-controlled systems allow individuals to set their own preferences for climate comfort. A high-efficiency heat-recovery system housed in the rooftop mechanical enclosure captures more than 90 percent of thermal losses, driving the structure’s overall energy use down by pre-heating or pre-cooling outside air.
- All outside air brought into the SEC is run through a whole-building air cascade, which conditions the air and allows it to be reused as many times as possible before being exhausted. Exhaust air is directed through a high-efficiency heat-recovery system, recapturing waste heat and mixing it with incoming fresh air for reuse. In non-laboratory spaces, an extensive natural ventilation system circulates fresh outdoor air throughout the building interior without the need for energy-intensive fan systems.
Source URL: https://www.constructionspecifier.com/harvard-universitys-new-building-features-hydroformed-facade-for-energy-efficiency/