By Steve Rizer
An energy-saving, “low-cost near infrared selective plasmonic smart window” technology that Heliotrope Technologies Inc. is developing could enter the commercial marketplace within three years, Guillermo Garcia, the Oakland, Calif.-based company’s chief technology officer, told ConstructionPro Week (CPW). This is one of several projects benefiting from the latest round of Small Business Innovation Research (SBIR) funding that the U.S. Department of Energy announced last week.
“Near infrared selective plasmonic smart coatings are the first electrochromic windows that dynamically block the sun’s heat without affecting visible light transmittance,” Garcia said. “By applying a small voltage (+/- 2 Volts), users can either block the sun’s heat (we refer to this as our ‘cool’ mode of operation) or allow the sun’s heat to enter the building (we refer to this as our ‘bright’ mode) without sacrificing any natural light. This is an ideal product that can maintain thermal management within a structure while still reducing the use of artificial lighting throughout the day. Traditional, smart window coatings primarily block visible light to initiate thermal management, which reduces the amount of energy savings one can achieve from these products. By selectively blocking the near infrared region of light (sun’s heat), we overcome this problem.”
Energy savings from this technology will vary, depending on geographical location, Garcia said. “The largest energy savings will be witnessed in northern regions where you get large swings of temperature change through the year. Initial models show that users can expect to save 5-11 kilowatt-hours (kWh) per square meter per year for commercial applications and 8-15 kWh per square meter per year for residential applications, in many regions on the order of 10 percent over the highest static coatings available in each region.”
But how expensive will this new technology be once it hits the market?
“Conventional static windows [low-emissivity windows] cost $100 per square foot installed to the end user,” Garcia said. “Current dynamic windows as sold by companies like View and Sage are as much as $200 per square foot installed. We believe our prices will fall in the middle or be closer to statics.”
The federal government is contributing $1 million in SBIR funding toward this Phase 2 development project.
The ConstructionPro Network member version of this article includes additional comments from CPW’s interview with Garcia, summaries of other new SBIR awards for promoting greener buildings, and coverage of other recent steps DOE has taken to encourage energy efficiency.