Windows that Outsmart the Elements

New Research Introduces Adaptable Smart Window Design that can Heat or Cool a House

Homeowners know that the type of windows in a house contribute to heating and cooling efficiency. And that’s a big deal – maintaining indoor temperatures consumes great amounts of energy and accounts for 20 to 40 percent of the national energy budgets in developed countries.

New research from the University of Pittsburgh and the University of Oxford takes energy efficient windows a step further by proposing a new “smart window” design that would harvest the sun’s energy in the winter to warm the house and reflect it in the summer to keep it cool. The work was published in the journal ACS Photonics and funded as part of the EPSRC Wearable and Flexible Technologies Collaboration (WAFT).

“The major innovation is that these windows can change according to seasonal needs,” explained Nathan Youngblood, assistant professor of electrical and computer engineering at Pitt and first author. “They absorb near infrared light from the sun in the winter and turn it into heat for the inside of a building. In the summer months, the sun can be reflected instead of absorbed.”

The film is made up of an optical stack of materials less than 300 nanometers thick, with a very thin active layer made of “phase change” materials that can absorb the invisible wavelengths of the sun’s light and emit it as heat. That same material can be “switched” so that it turns those wavelengths of light away instead.

“Importantly, visible light is transmitted almost identically in both states, so you wouldn’t notice the change in the window,” Youngblood noted. “That aesthetic consideration is critical for the adoption of green technologies.”

The material could even be adjusted so that, for example, 30 percent of the material is turning away heat while 70 percent is absorbing and emitting it, allowing for more precise temperature control.

Harish Bhaskaran, professor at Oxford’s Materials Department, who led the research and heads the WAFT consortium said, “Here, we exploit tuning how invisible wavelengths are transmitted or reflected to modulate temperature. These ideas have come to fruition with the aid of our long-standing industrial collaborators, and are the result of long-term research.”

The researchers estimate that using these windows – including the energy required to continued on next page

Windows that Outsmart the Elements...

continued from page 11 control the film – would save 20 to 34 percent in energy usage annually compared to doublepaned windows typically found in homes.

To create and test their prototypes, the researchers worked with Bodle Technologies, a company that specializes in ultra-thin reflective films that can function as displays by controlling color and light, as well as Eckersley O’Callaghan, a leading engineering and architectural firm, and Plasma App, a thin films company.

“This work demonstrates yet another interesting optoelectronic application of Phase Change Materials with the potential to significantly improve our everyday life,” said Peiman Hosseini, CEO of Bodle Technologies. “The commercialization of PCM-based tuneable low-e glass panels still has several significant challenges left to overcome; however, these preliminary results prove that the long developmental road ahead is certainly warranted. I believe this technology should be part of any future holistic policy approach tackling climate change.”

CASPR Celebrates One Year Aboard the ISS

CASPR – the Configurable and Autonomous Sensor Processing Research system – has been hard at work on the International Space Station (ISS).

The system of new space computers and sensors was created at the University of Pittsburgh’s NSF IUCRC Center for Space, High-performance, and Resilient Computing (SHREC). Since powering up in January 2022, it has been collecting data and imagery at low ground-resolved distances, meaning it can see fine details in each image. Roads and houses, even airplanes taxiing on an airport runway, are all visible with CASPR’s incredible high-resolution binocular telescope and space computing capabilities.

And the SHREC ground station isn’t in Houston or Florida, but rather headquartered in Schenley Place on Pitt’s Oakland campus.

“When you’re at the ground station, you have a window looking out over the entire planet in your office, and you get a little bit of what it’s like to see the earth from space,” said Evan Gretok, graduate student at Pitt and CASPR operations lead.

“This data, and these images – we’re theoretically the first people to see them,” added CASPR Project Manager Seth Roffe, also a graduate student at Pitt.

The space computing system will continue pushing boundaries for at least another year, as its stay aboard the ISS was recently extended through December 2023. After its work is finished, CASPR will be disconnected from the ISS and will hurdle toward earth, getting a closer look at the planet it surveyed before eventually burning up in its atmosphere.

Pitt Students Hone Engineering (and Life) Skills in Electric Boat Competition

Engineering students at University of Pittsburgh, until recently, were offered little hands-on experience with electric vehicles of any type. So last year, when then-junior Nick Genco saw an opportunity for a club at Pitt dedicated to racing electric boats in the Promoting Electric Propulsion (PEP) for Small Craft competition held by the American Society of Naval Engineers, he jumped in. That was the summer of 2021. The race was the following May. Plenty of time, right?

“I didn’t grow up boating. I played basketball in high school,” Genco says. “I really knew nothing about boating or the effects of getting on a plane or anything like that. As I got more into the actual boating aspects, I found out there was a lot to learn.”

Pittsburgh Electric Propulsion, the name chosen for the university sponsored student design team, now includes more than 40 undergraduates studying 10 different disciplines of engineering as well as finance, economics, marketing, computer science and business information systems. With the university still in Covid lockdowns, however, they couldn’t meet to actually build a boat until late October. For trim and displacement measurements, they carried their fully rigged 13-foot Zodiac Milpro ERB400 inflatable up infamous Cardiac Hill to the nearest warm water – Pitt’s indoor swimming pool.

Their electric motor, built into a 1968 Mercury Thunderbolt 500 outboard shell, went untested until race day. Even plagued with during-race repairs jury-rigged by the boat’s skipper, Luke Sowinski, the club’s Cathy – named for the

Cathedral of Learning building on campus – still managed 11 mph and third place in a fleet of seven entries competing on Pohick Bay, off the Potomac River outside of Washington D.C.

While funding remains challenging, Cathy seems to be right on track for June. As of this writing, Pitt Electric Propulsion recently partnered with hydroplane racer Thomas Schlarb to campaign 70 mph electric-powered C-Stock hydroplanes. The first race is in June. Plenty of time, right?

The full article appears in Boating magazine.