PARIS: Scientists said yesterday they had created a window coating that can be switched electrically to regulate the amount of heat and light that enters a building. A team of molecular and material scientists from the United States and Spain created a transparent film using nanocrystals -- microscopic clusters of atoms that can change the wavelength of light.
“Smart windows and specifically electrochromic windows (which change colour or transparency with an electric charge) have been developed already, but our solution is the first to offer integrated control over heat and visible light,” study co-author Delia Milliron of the Lawrence Berkeley National Laboratory in California said.
In the design, published in the journal Nature, the window is an electrochemical cell with two glass panes separated by an electrically conductive electrolyte liquid. The film is placed on one pane to create an electrode which passes an electric charge to a counter-electrode on the other pane. With no electric current, the window remains transparent. A charge causes the nanoparticles in the coating to start blocking heat waves while the window remains transparent -- a further charge causes light also to be blocked.
According to University of Texas engineer Brian Korgel, who commented on the study, residential and office buildings account for about 40 percent of energy use and 30 percent of energy-related carbon emissions in the United States.
AFP
