CAT Scans for Cities

Researchers are using thermal imaging to diagnose energy efficiency in the built environment

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Thermal Cities/Steve Lowe

From any urban street corner, it’s difficult to tell which apartment buildings are energy efficient, which residents are consuming the most energy, or which office complexes are retaining the most heat from the sun, boosting the need for tenants inside to crank up the air conditioning. Energy use and, more specifically, energy efficiency, are among the most critical issues for cities to measure, map, and understand in an era of scare resources and climate change. But they’re also nearly impossible to see.

Infrared cameras, however, reveal an entirely different urban landscape. These images capture temperature along with scene. They can catch leaky buildings and baking asphalt. They portray the built environment in thermal portraits as vibrant as the living street life below.

Courtesy Massachusetts Institute of Technology

Steve Lowe has used thermal images as a kind of art portraying the architectural patterns of London. David Sailor, a professor of mechanical engineering at Portland State University, has used thermal images to capture the effects of urban heat islands. And researchers at the MIT Field Intelligence Lab have taken the technology (a camera plus sophisticated software) one step further to capture not just the presence of energy, but also the precise windowsills, joists and doorways where it seeps from drafty buildings.

“From our point of view, medical diagnostic imaging is something that’s been around for a long, long while,” says Long Phan, one of the MIT researchers. “We had CAT scans and MRIs for many, many years. Now what we’re doing is we’re taking that mind frame and now instead of diagnosing people, we’re diagnosing objects such as homes, commercial buildings, industrial refineries and manufacturing centers.”

Courtesy Thermal Cities/Steve Lowe

The MIT researchers are pioneering “energy diagnostic imaging.” “It’s a completely new science,” Phan says, and one that can be used in energy audits to identify both energy-inefficient buildings and exactly what’s gone wrong with them. The diagnostic images are also, well, beautiful.

Lowe’s images were taken in a very different context – in conjunction with the 2008 London Festival of Architecture.

“It’s amazing,” Lowe says of his thermal images, “the kind of revelations you can come up with that engage with more than just an engineering audience.”

About the Author

  • Emily Badger is a former staff writer at CityLab. Her work has previously appeared in Pacific StandardGOODThe Christian Science Monitor, and The New York Times. She lives in the Washington, D.C. area.