Beating the heat: Designing cooling for bodies in motion

Effective and efficient cooling strategies are increasingly necessary in a warming climate. This is in part because humans continuously generate heat through metabolism, releasing it into the environment around them. Dorit Aviv views the built environment—buildings, roads, and other human-made infrastructure—as the site of a constant thermodynamic exchange between humans and space.

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She established the Thermal Architecture Lab to study how humans, technology, and design intersect, paving the way for the development of novel, creative approaches to cooling people efficiently.

“The goal was to create a place where we could make an impact on building performance, energy use, and people’s health through the integration of design and building systems,” says Aviv, an assistant professor at the Stuart Weitzman School of Design.

Penn Today spoke with Aviv, director of the Thermal Architecture Lab, about the vision of the lab and some of her current projects.

Human-centered cooling technologies

Global temperatures are rising, and the effects are especially severe for communities trapped in urban heat islands, where concrete and asphalt amplify the heat, explains Aviv.

“Shade is really important,” she says. “But sometimes people need more than shading, especially during extreme heat events. But there is a lack of infrastructure to serve people who don’t have access to cooling.”

To address this need, several projects in the lab focus on considering the materials and forms of buildings and structures from the perspective of thermodynamics, seeing them as active agents in the transfer of heat from the human body and its environment.

“Our technologies are very human-centered and embedded in how the human body interacts with its environment,” explains Aviv. “If we are sitting, we actually transfer heat differently than if we’re standing or if we’re walking.”

Structures need to be designed with how people use them. “In buildings, for example,” Aviv says, “people are sitting or standing or walking around, so you want to design for all of those conditions.” For other structures such as cooling stations or bus stops, the needs are different.”

Aviv and her team collaborated with Sara Jacoby from the School of Nursing, researchers from the School of Engineering and Applied Science, and North10, a community organization serving the Hunting Park-East Tioga neighborhoods in North Philadelphia, to develop TENOPY, a cooling station that can act as a bus stop.

People sit and stand at a bus stop, says Aviv, so the structure needed to be able to cool people in both of those positions. Her team used conductive-based cooling in the benches and radiant panels where people stand—all powered by solar panels.

They found that the structures reduced radiant heat levels by more than 20°C compared to nearby unshaded areas. Community members reported high levels of thermal comfort while in the shelters. These findings are published in Sustainable Cities and Society.

A second publication, a policy digest released by the Kleinman Center for Energy Policy, examines how this successful pilot in Philadelphia can serve as a framework for community-centered urban cooling.

Aviv and her collaborators at Henning Larsen Architects and AIL Research have applied these approaches to a larger cooling structure that was installed on Governor’s Island in New York last summer and a smaller, foldable, and more portable one for outdoor events.

They are currently working on designing a chair.

“We wanted to explore how much cooling we can do just with furniture,” says Aviv, describing the low-carbon concrete chair that she and her collaborators, Weitzman’s Masoud Akbarzadeh and Shu Yang of Penn Engineering, created using 3D printing in which they embedded the cooling system. “We needed an ergonomic design that really maximizes the contact area of the body with the chair,” she adds. “We wanted to know how much cooling you can get if someone is lounging.”

Handling urban heat

Aviv’s work also focuses on assessing heat specifically in urban environments. She is working on a project with the City of Philadelphia and Penn Engineering’s Russell Composto and his group that examines the effectiveness of reflective surfaces in mitigating heat.

“This project focuses on the thermal experience you have when you are walking through the city,” she says. “Everyone thinks that you can reflect the sun away from pavements, that that will solve the heat problem because now the pavement is not absorbing the heat.”

But the heat has to go somewhere, Aviv says, namely back onto the people walking on the sidewalk. “While you are significantly decreasing the surface temperature of the sidewalk, you are also increasing the amount of solar radiation received by the people walking on it.”

This work highlights the complexities of heat transfer in buildings and in cities, she adds. “While reflective roofs are extremely efficient in preventing overheating of indoor spaces, reflective pavements are not a magic solution.”

Aviv is also partnering with the Netter Center for Community Partnerships to work with high school students on ways to reduce heat in school courtyards.

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“Thinking about movement, school courtyards are an interesting case study,” she says. “Students are supposed to be able to move there—it’s their outdoor space. But because of their design, they are often extreme heat islands. And students don’t want to go outside.”

Aviv and her students are investigating how surface materials, vegetation, and shading interventions can mitigate urban heat stress in educational environments.

“My goal is to develop research methodologies to measure and characterize both outdoor and indoor heat,” says Aviv. “Then we can research novel technologies and design strategies to simultaneously reduce buildings’ energy demand and provide thermal shelter to people in a warming world.”