Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Smarter window materials can control light and energy

23.07.2015

Researchers in the Cockrell School of Engineering at The University of Texas at Austin are one step closer to delivering smart windows with a new level of energy efficiency, engineering materials that allow windows to reveal light without transferring heat and, conversely, to block light while allowing heat transmission, as described in two new research papers.

By allowing indoor occupants to more precisely control the energy and sunlight passing through a window, the new materials could significantly reduce costs for heating and cooling buildings.


The illustration demonstrates the dark, bright and cool mode made possible by the researchers' new architected nanocomposite. The team organized the two components of the composite material to create a porous interpenetrating network. This organization enables substantially faster switching between modes.

Credit: Cockrell School of Engineering

In 2013, chemical engineering professor Delia Milliron and her team became the first to develop dual-band electrochromic materials that blend two materials with distinct optical properties for selective control of visible and heat-producing near-infrared light (NIR). In a 2013 issue of Nature, Milliron's research group demonstrated how, using a small jolt of electricity, a nanocrystal material could be switched back and forth, enabling independent control of light and energy.

The team now has engineered two new advancements in electrochromic materials -- a highly selective cool mode and a warm mode -- not thought possible several years ago.

The cool mode material is a major step toward a commercialized product because it enables control of 90 percent of NIR and 80 percent of the visible light from the sun and takes only minutes to switch between modes. The previously reported material could require hours.

To achieve this high performance, Milliron and a team, including Cockrell School postdoctoral researcher Jongwook Kim and collaborator Brett Helms of the Lawrence Berkeley National Lab, developed a new nanostructured architecture for electrochromic materials that allows for a cool mode to block near-infrared light while allowing the visible light to shine through. This could help reduce energy costs for cooling buildings and homes during the summer. The researchers reported the new architecture in Nano Letters on July 20.

"We believe our new architected nanocomposite could be seen as a model material, establishing the ideal design for a dual-band electrochromic material," Milliron said. "This material could be ideal for application as a smart electrochromic window for buildings."

In the paper, the team demonstrates how the new material can strongly and selectively modulate visible light and NIR by applying a small voltage.

To optimize the performance of electrochromics for practical use, the team organized the two components of the composite material to create a porous interpenetrating network. The framework architecture provides channels for transport of electronic and ionic change. This organization enables substantially faster switching between modes.

The researchers are now working to produce a similarly structured nanocomposite material by simple methods, suitable for low-cost manufacturing.

In a second research paper, Milliron and her team, including Cockrell School graduate student Clayton Dahlman, have reported a proof-of-concept demonstrating how they can achieve optical control properties in windows from a well-crafted, single-component film. The concept includes a simple coating that creates a new warm mode, in which visible light can be blocked, while near-infrared light can enter. This new setting could be most useful on a sunny winter day, when an occupant would want infrared radiation to pass into a building for warmth, but the glare from sunlight to be reduced.

In this paper, published in the Journal of the American Chemical Society, Milliron proved that a coating containing a single component ¬-- doped titania nanocrystals -- could demonstrate dynamic control over the transmittance of solar radiation. Because of two distinct charging mechanisms found at different applied voltages, this material can selectively block visible or infrared radiation.

"These two advancements show that sophisticated dynamic control of sunlight is possible," Milliron said. "We believe our deliberately crafted nanocrystal-based materials could meet the performance and cost targets needed to progress toward commercialization of smart windows."

###

Both studies received funding from the U.S. Department of Energy and the Welch Foundation, as well as the NSF Graduate Fellowship Program.

The University of Texas at Austin is committed to transparency and disclosure of all potential conflicts of interest. The lead UT investigator involved with this project, Delia Milliron, is the chief scientific officer and owns an equity position in Heliotrope Technologies, an early-stage company developing new materials and manufacturing processes for electrochromic devices with an emphasis on energy-saving smart windows. Milliron is associated with patents at Lawrence Berkeley National Laboratory licensed to Heliotrope Technologies. Collaborator Brett Helms serves on the scientific advisory board of Heliotrope and owns equity in the company.

Media Contact

Sandra Zaragoza
Zaragoza@utexas.edu
512-471-2129

 @UTAustin

http://www.utexas.edu 

Sandra Zaragoza | EurekAlert!

More articles from Architecture and Construction:

nachricht Living bridges: How traditional Indian building techniques can make modern cities more climate-friendly
18.11.2019 | Technische Universität München

nachricht Corrosion - Slow Decay
22.10.2019 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

All articles from Architecture and Construction >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Machine learning microscope adapts lighting to improve diagnosis

Prototype microscope teaches itself the best illumination settings for diagnosing malaria

Engineers at Duke University have developed a microscope that adapts its lighting angles, colors and patterns while teaching itself the optimal...

Im Focus: Small particles, big effects: How graphene nanoparticles improve the resolution of microscopes

Conventional light microscopes cannot distinguish structures when they are separated by a distance smaller than, roughly, the wavelength of light. Superresolution microscopy, developed since the 1980s, lifts this limitation, using fluorescent moieties. Scientists at the Max Planck Institute for Polymer Research have now discovered that graphene nano-molecules can be used to improve this microscopy technique. These graphene nano-molecules offer a number of substantial advantages over the materials previously used, making superresolution microscopy even more versatile.

Microscopy is an important investigation method, in physics, biology, medicine, and many other sciences. However, it has one disadvantage: its resolution is...

Im Focus: Atoms don't like jumping rope

Nanooptical traps are a promising building block for quantum technologies. Austrian and German scientists have now removed an important obstacle to their practical use. They were able to show that a special form of mechanical vibration heats trapped particles in a very short time and knocks them out of the trap.

By controlling individual atoms, quantum properties can be investigated and made usable for technological applications. For about ten years, physicists have...

Im Focus: Images from NJIT's big bear solar observatory peel away layers of a stellar mystery

An international team of scientists, including three researchers from New Jersey Institute of Technology (NJIT), has shed new light on one of the central mysteries of solar physics: how energy from the Sun is transferred to the star's upper atmosphere, heating it to 1 million degrees Fahrenheit and higher in some regions, temperatures that are vastly hotter than the Sun's surface.

With new images from NJIT's Big Bear Solar Observatory (BBSO), the researchers have revealed in groundbreaking, granular detail what appears to be a likely...

Im Focus: New opportunities in additive manufacturing presented

Fraunhofer IFAM Dresden demonstrates manufacturing of copper components

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Dresden has succeeded in using Selective Electron Beam Melting (SEBM) to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

High entropy alloys for hot turbines and tireless metal-forming presses

05.11.2019 | Event News

 
Latest News

Scientists first to develop rapid cell division in marine sponges

21.11.2019 | Life Sciences

First detection of gamma-ray burst afterglow in very-high-energy gamma light

21.11.2019 | Physics and Astronomy

Research team discovers three supermassive black holes at the core of one galaxy

21.11.2019 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>