CASE STUDY:
Charles Hostler Student Center

Rooted in Beirut: A new student center for the American University of Beirut combines state-of-the-art sustainable innovation with the region’s traditional solutions.

By Sarah Amelar

Sited on a steep hillside overlooking the Mediterranean, the American University of Beirut (AUB)’s 73-acre main campus is so lush it’s called “The Garden of Beirut.” AUB’s original historic section, dating back to the 19th century, meanders across the hilltop, while its later, lower section extends down to the Corniche, the Lebanese capital’s grand waterfront boulevard.

To usher in the 21st century, a campus master plan by Sasaki Associates, with Machado and Silvetti, recommended long-range strategies with upgrades to existing conditions. Sustainability was key. Clearly the plan’s first new building, the Charles Hostler Student Center, needed to be a model of environmentally responsive design for AUB and the region.

For this 104,000-square-foot center—to include athletics facilities, an auditorium, a cafeteria, and underground parking—the architects challenged and advanced the master plan’s green guidelines. “We realized we couldn’t just import and impose standard rules of thumb and sophisticated technologies from abroad,” says Vincent James, whose Minneapolis-based firm, Vincent James Associates Architects (VJAA), won the commission, following an invited international competition. “We had to think deeply about vernacular solutions, about the ways people traditionally lived in this climate and culture.”

Where a prior concept design called for a large building, fronting a similarly scaled plaza, VJAA, with Transsolar climate engineers and Hargreaves Associates landscape architects modified the strategy. Around a cluster of five new, low-lying, rectilinear volumes, linked underground or by bridges, they created a continuous, layered field of outdoor habitable spaces: courtyards, gardens, green roofs, paths, a cafe, and lookouts, all facing the sea. This rich continuum integrates the formerly disjointed upper and lower campuses, negotiating elevation changes from hilltop to waterfront.

Inspiration for scale and massing came from the campus’s historic section, as well as the classic Beirut house, which steps down a slope, oriented seaward to facilitate the flow of breezes. In such shaded courtyard dwellings, as VJAA principal Jennifer Yoos observes, “people move with the sun, using spaces differently at different times of day.” Similarly calibrating architecture to climate, the design team sought spatial diversity—inside and out—using buildings to cast shadows and modulate air currents, tempering courtyard microclimates for comfort. These outdoor gathering zones form what James calls “social connective tissue” between more structured interior spaces.

Like fountains in traditional Medit-erranean courtyards, two water-walls—stainless-steel mesh scrims beneath smooth “sheets” of running water—override noise and modulate outdoor climate. The planted roofs increase insulation, while enhancing terraced views from the upper campus.

Bucking the generic notion that south-facing buildings, on a long east-west axis, are sustainably ideal, the architects oriented the $18 million Hostler Center northward, optimizing sea breezes and views. To the east and west, long, mostly solid masonry walls, with shading devices, block the harshest rays.

The complex draws on durable, locally available building methods and materials: Syrian sandstone cladding, concrete posts and beams, terrazzo flooring, and interior plaster surfaces. Adapting Lebanon’s traditional exterior wall, the architects devised a double-shell, stone-and-concrete, insulated cavity wall, dramatically reducing its precursor’s U-value, for a highly efficient envelope.

Strategically placed exterior louvers of pre-cast concrete or locally crafted aluminum shade the interior, while operable skylights (over the pool and gymnasium) enhance ventilation. Oriented for prevailing winds and local airflow conditions, 60 percent of the interior offers natural ventilation through large operable openings. Requiring virtually no daytime electrical illumination, 67 percent of the interior is sunlit, through low-E glazing.

Beirut’s unreliable infrastructure, still reeling post-civil war, made autonomy essential for AUB and its new construction. In response, the Hostler Center’s innovative climate control can cool the entire lower campus. A geothermal system, it runs water from deep, cold sea wells, through a closed- loop heat exchanger to radiantly cool highly populated interior zones. At the loop’s end, the water returns to the sea in a temperature-compatible area, protecting marine life. The electricity draw—only to operate low-energy pumps—is negligible compared with conventional cooling. This inspired solution eliminates rooftop chillers (noisy energy guzzlers and eyesores from the upper campus).

Solar roof panels, atop the gymnasium and swimming pavilion, heat the pool and shower water. Radiant heating, relying exclusively on waste heat or steam from AUB’s physical plant, can warm the pool deck and (via ceilings) other interior spaces (though the climate and efficient insulation make that need rare).

With potable water a scarce resource in Beirut, the center recycles gray water, plus rain from site drains and rooftops, for toilets and irrigation of native, drought-resistant landscaping. (All native trees displaced during construction were preserved and replanted on site.)

One of the region’s first strong attempts at modern sustainable design, the Hostler Center is highly attuned to its place: a fusion of traditional vernacular with state-of-the-art solutions. “We weren’t just coming in with standards coined in Europe or the US,” says James. “People in Beirut tell us they appreciate the approach.”

Sarah Amelar is a writer, editor, and architect.