Get Sust! Issue 33

Windows worth watching

Swedish innovator ChromoGenics is investing US$6 million to scale-up production of its award-winning electrochromic technology - a patented glass laminate technology that can cut glare and can help reduce or eliminate the need for air-conditioning in buildings and vehicles.

With the announcement of this investment, ChromoGenics is hoping to tap into the growing market for energy-efficient building products.

The company’s technology, which received the Most Promising Technology Award at the 2007 Cleantech Forum XIII in Frankfurt, Germany, creates thin plastic foils (<0.5mm) that are applied to glass or used as laminates between layers of glass. When a low voltage (1.5V) is applied to the foil it darkens, thus automatically regulating the amount of light and heat radiation that passes through the pane.

The reversible electrochromic process was discovered nearly 40 years ago, and there was a flurry of research activity into the properties of these materials in the mid-1980s when materials scientists began to investigate the possibility of developing ‘smart windows’. Such windows could improve both energy efficiency (because they reduce solar gain, thereby minimising the need for air-conditioning) and indoor comfort (less glare and thermal discomfort).

The key to the successful development of useful products was to create thin and flexible films for ‘membrane architecture’, where they can be used to create a building envelope that actively moderates energy flows.

Full details of the technology and an assessment of its ability to reduce a building’s energy usage were presented in a recent feature article in the Royal Society of Chemistry’s Journal of Materials Chemistry.

Learn more:

	•	ChromoGenics was founded in 2003 by Professor Claes Granqvist and his team at the Division of Solid State Physics at Uppsala University in Sweden www.chromogenics.se.
	•	Source: ‘Electrochromics for smart windows: thin films of tungsten oxide and nickel oxide, and devices based on these’, Gunnar A. Niklasson and Claes G. Granqvist, Journal of Materials Chemistry, 17, 127-156; downloadable PDF at www.chromogenics.se.>