Quantcast
Energy
Convention Center, Shanghai, China. Xinzheng / Getty Images

These Windows Can Generate Electricity And Provide Insulation

By Marlene Cimons

The windows of many cars and buildings often are tinted with a film that shuts out unnecessary sunlight, an energy efficiency measure that helps lower heating and cooling costs. Other types of environmentally friendly windows feature a coating of see-through solar cells that transform the windows into mini generators of electricity. But you probably won't find any windows anywhere that can do both. Not yet anyway.


This could be about to change. Chinese scientists have invented a new material that can both block the sun and produce power. They predict that windows outfitted with this product—or even window curtains that have it—eventually could cut the average household's electric bills by half or more.

"We combine both material innovation and optical thin film design to achieve the goal of combining both solar electricity generation and heat insulation in one single film," said Hin-Lap (Angus) Yip, a professor of materials science and engineering at the South China University of Technology. "Our energy efficiency for the house is kind of double: power generation and power saving."

Tinted car windows block light.Pixabay

Constructing a prototype that could simultaneously make electricity and prevent excessive heat required the scientists—who also included Fei Huang, also of South China University—to perform a balancing act between harvesting light to make electricity and blocking it, mixing and matching from among a variety of materials and chemical compounds to find exactly the right working combination.

Eventually, they designed a product that allowed visible portions of sunlight to pass through, but rejected infrared light, which is "a major heating culprit," Yip said. The researchers then transformed the near-infrared region in-between into an electric current.

"The major material we used for turning the solar light to electricity was a polymer semiconductor," Yip said. "We can design the chemical structure and tune [its] absorption property. This organic material has very unique absorption property, which can selectively absorb the near-infrared light, [but] allow a major portion of visible light to pass through it, making it a perfect material for semitransparent photovoltaic (PV) window application."

Current solar cell technology based on silicon or other inorganic semiconductors is not suitable for photovoltaic window applications "as they are opaque and dull in appearance," he added. "Instead, we can make organic photovoltaics into semi-transparent, lightweight and colorful films that are perfect for turning windows into electricity generators and heat insulators."

A paper describing the research appears in the journal Joule.

Yip said the material was similar to the pigment used in printing newspapers or coating cars, "but more functional," he said.

Actually, we can manufacture the polymer solar cell on flexible substrate using roll-to-roll printing process, just like the way we print our newspaper. If you compare this to the energy intensive process required for the production of silicon solar cells, the production of polymer solar cells consumes less energy, with a lower carbon footprint.

The material has a number of potential applications. Because it's a flexible and roll-able film, Yip thinks it would make a great window curtain. "Nowadays, many curtains are controlled electrically to open and shut, and since our photovoltaic window film will generate electricity, the same electrical circuit can be used to carry out the power, which can be then directly used or stored to power other facilities in the house," he said.

He also sees their value for use in self-powered greenhouses. "It just requires tailoring the optical property of the photovoltaic window film, as plants mainly absorb blue and red light, which is why they are green," he said. "So the design of the photovoltaic window film for greenhouse applications will have to maximize the transmission of blue and red light. This is feasible through new material design and optical engineering."

The scientists estimate that installing windows with dual purpose electricity-generating and heat-insulating properties could reduce the average household's reliance on external electric sources by more than 50 percent, although this figure assumes that every square inch of every window would have panels made of multifunctional solar cells.

Yip pointed out that the researchers didn't even use "the best organic photovoltaics that are out there in this field," for their own research demonstration, he said. "Their efficiency is improving rapidly, and we expect to be able to continuously improve the performance of this unified solar-cell window film. Making heat-insulating multifunctional semitransparent polymer solar cells is just the beginning of exploring new applications of organic photovoltaics."

Yip said it would be easy to scale up the product for widespread use and—although it initially may be more expensive than traditional films—it could pay for itself fairly quickly. "We think that polymer based solar cells will have a much shorter energy payback time compared to inorganic photovoltaics, as they can be manufactured using low energy printing processes," he said.

"In terms of the cost of the film, since it has a very similar structure to current heat insulating film—but with just a few additional layers—I expect it will be slightly higher than current window film," he added. "But since its energy efficiency can be double, we believe the cost payback time will be very short, maybe within three to four years."

He projected that the materials could be in commercial use within five years.

"It's been about 25 years from the discovery of polymer solar cells until now," he said. "We've had some very nice progress improving the efficiency and stability of polymer solar cells. If we can identify the best materials and processes to scale up these photovoltaic technologies in the next few years, maybe we will be able to see them everywhere on their 30th anniversary."

Related Articles Around the Web
Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Health
A smoky haze obstructs the view of the San Francisco skyline on Aug. 24 in San Francisco, California. Justin Sullivan / Getty Images

Smoke Is a Big Health Risk as California Wildfires Rage On

By Nneka Leiba

Deadly wildfires continue to blaze in Northern and Southern California. Dozens of people are dead, hundreds more missing and entire communities have been destroyed.

Keep reading... Show less
Popular
Westend61 / Getty Images

EcoWatch Gratitude Photo Contest: Submit Now!

EcoWatch is pleased to announce its first photo contest! Show us what in nature you are most thankful for this Thanksgiving. Whether you have a love for oceans, animals, or parks, we want to see your best photos that capture what you love about this planet.

Keep reading... Show less
Health
Leela Cyd / Photolibrary / Getty Images

EPA Finds Replacements for Toxic 'Teflon' Chemicals Toxic

By Anna Reade

The U.S. Environmental Protection Agency (EPA) has released draft toxicity assessments for GenX chemicals and PFBS, both members of a larger group of chemicals known as per- and polyfluoroalkyl substances (PFAS). GenX and PFBS are being used as replacement chemicals for PFOA and PFOS, the original Teflon chemicals that were forced off the market due to their decades-long persistence in the environment and their link to serious health harms in exposed people and wildlife.

Keep reading... Show less
Science
Demonstrators at the Earth Day March for Science Rally on April 22, 2017 in Washington, DC. Paul Morigi / Getty Images

New Report Details Trump's Destructive War on Science—And How the New Congress Can Fight Back

By Jessica Corbett

A coalition of watchdog and advocacy organizations on Thursday released a new report detailing the Trump administration's nearly two-year war on science and how Congress can fight back.

Produced by 16 groups including the Union of Concerned Scientists (UCS), Defenders of Wildlife and Greenpeace, Protecting Science at Federal Agencies: How Congress Can Help argues that while "scientific integrity at federal agencies has eroded" under President Donald Trump, "Congress has the power to halt and repair damage from federal agencies' current disregard for scientific evidence."

Keep reading... Show less
Sponsored
Popular
Downtown Houston surrounded by flooding and mist after Hurricane Harvey. Prairie Pictures / The Image Bank / Getty Images

Houston’s Tall Buildings and Concrete Sprawl Made Harvey’s Rain and Flooding Worse

The science is clear that in order to prevent more extreme weather events like hurricanes, we need to stop burning fossil fuels. Thursday, EcoWatch reported on a study that found major hurricanes in the past decade were made five to 10 percent wetter because of global warming, and another study last year calculated that the record rainfall that flooded Texas during Hurricane Harvey was made three times more likely due to climate change.

Keep reading... Show less
Health
Roundup for sale at a hardware store in San Rafael, CA, on July, 9. JOSH EDELSON / AFP / Getty Images

Second CA Glyphosate Trial Scheduled for Elderly Couple in Declining Health

The first trial claiming long-term use of Monsanto's Roundup weedkiller caused the plaintiff's cancer ended with a $289 million jury verdict in favor of the plaintiff, though that was later reduced by a judge to $78 million.

Now, Monsanto's next date in the judgment seat in California has been set for March 18.

Keep reading... Show less
Sponsored
Climate
Sea ice in the Arctic Ocean. NASA

Not Enough Ice to Drill the Arctic! Offshore Oil Drilling a 'Disaster Waiting to Happen'

Last month, the Trump administration approved the first offshore oil drilling development in federal Arctic waters, which environmentalists fear will ramp up carbon pollution that fuels climate change.

But here's the ultimate irony: Hilcorp Alaska's project—which involves building a 9-acre artificial drilling island in the shallow waters of the Beaufort Sea—has been delayed because of the effects of climate change, Alaska Public Media reported.

Keep reading... Show less
Insights/Opinion
Dominion Energy's headquarters in Richmond, Virginia. VCU CNS

Cash Buys Elections—and Continued Fossil Fuel Dominance

By Wenonah Hauter

Last week, the fossil fuel industry successfully squashed several local measures it didn't like—thanks to the more than $100 million it shelled out to oppose them.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!