PhD Architecture graduate group faculty Dr. Dorit Aviv, Heat Islands and the Thermal Lab. Extract from “Testing a novel, community-driven response to heat islands in Philadelphia" by Erica Moser

July marked the 14th month in a row of record high global temperatures, and as the month ended, the National Weather Service said Philadelphia was on track for its third warmest summer since 1874. While 94° days are hardly pleasant for suburbanites, heat can be worse for residents in pockets of Center City, South Philadelphia, and North Philadelphia.

In Hunting Park, a North Philadelphia neighborhood, temperatures can be as much as 20° hotter than in other parts of the city. Operating out of the Lenfest Center, the nonprofit North10 serves the Hunting Park-East Tioga area by offering youth programs, workforce training, affordable housing, a community market, and more. Nikki Bagby, chief external affairs officer, says people of all ages who come for services wait in the heat to catch a bus, and the bus stop has no overhang.

University of Pennsylvania researchers from the Weitzman School of Design, School of Nursing, and School of Engineering and Applied Science developed a novel prototype to address this issue: a solar-powered wooden bus shelter that provides shade and radiant cooling.

This is thanks to a grant from the Penn Community Collaboratory for Co-Creation (Penn4C), a joint initiative from Penn Nursing and Penn Engineering “based on the recognition that technological solutions should be designed with active engagement of marginalized communities.”

Dorit Aviv, assistant professor of architecture and director of the Thermal Architecture Lab in Weitzman, led the research, design, and construction of the prototype with a team of students, while associate professor of nursing Sara Jacoby provided messaging on the health impacts of heat and surveyed community members. The prototype is called Tenopy—a canopy created in collaboration with North10—and community members tested it out one day in August.

“We are aiming to provide an experience of being outside in the heat and then walking in here, sitting, and feeling relief while still being in an open-air structure,” Aviv says. “This can have important implications for how we think about urban cooling shelters for the future, especially given the need for open-air structures in light of what we’ve seen during the COVID pandemic. We also learned a lot from the community collaboration, and we hope that if the pilot is successful, we can work together toward long-lasting solutions.”

The prototype was designed as a temporary shelter, while installing a permanent structure involves material and structural enhancements and getting necessary permits for installation, Aviv says. She wants to see this experiment turned into a more permanent solution and replicated elsewhere.

“The neat thing about it is you really need this cooling when you have a lot of sun, like today,” Aviv said one 93° day in July, “so that means it will be powered as long as you need cooling.” Aviv began working with Penn4C and Bagby (from North10) last October, meeting with Bagby to get input on the design. Ji Yoon Bae, now a third-year Ph.D. student in architecture working in Aviv’s lab, joined the project in May and helped design the structure.

“I was super interested in the environmental aspect of design discourse,” Bae says. He envisioned an undulating angle for the backrest, so people can comfortably transition from sitting to standing, and designed the ceiling height on an angle to accommodate people of different ages.

Hanzhong Luo, a Master of Architecture student, and Shuo-Hsuan “Wayne” Chang, a Master of Science in Design in Environmental Building Design (MSD-EBD) student, later joined the project to help Bae with woodcutting and structure assembly, which began in early June. The students also used thermal cameras to document the effects of the shelter.

Thermal engineer Eric Teitelbaum of AIL Research in Hopewell, New Jersey, an architecture lecturer at Penn and longtime collaborator with Aviv, worked with the team throughout the process and designed the cooling equipment.

Aviv says a major part of her research is finding alternatives to air conditioning, which consumes a lot of energy and requires an enclosed environment. In 2020, she and Teitelbaum co-authored a paper presenting results from an outdoor radiant-cooling pavilion they constructed in Singapore. “It successfully makes people feel comfortable in conditions exceeding 30°C and 65% relative humidity,” the authors reported.

Their work challenged two views that have kept radiant-cooling technologies from widespread commercial adoption: that the low temperature required will form condensation in humid environments, and that cold surfaces will still cool adjacent air via convection, limiting the effectiveness of radiant cooling.

The researchers used an infrared-transparent polyethylene membrane to separate the cooling surface from the humid air and thus prevent condensation, an approach also taken with Tenopy. But Tenopy is testing the cooling bench for the first time.

The Ramboll Foundation recently selected Aviv, Teitelbaum, and William Braham, the Andrew Gordon Professor of Architecture and director of the MSD-EBD Program, as recipients of a $149,000 grant to develop an architectural application of their membrane-assisted radiant cooling technology. This takes the form of a mobile structure that could be disassembled and then reassembled to be tested at various partner sites.

The grant and collaboration with architectural firm Henning Larsen “has the potential to make this technology accessible and deployable in the places that need it the most,” Aviv says.