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 Smart buildings through innovative membrane roofs and façades
31.08.2017 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

nachricht Concrete from wood
05.07.2017 | Schweizerischer Nationalfonds SNF

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: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>