this window can go from transparent to tinted while converting sunlight into electricity

scientists at the U.S. department of energy’s national renewable energy laboratory (NREL) have reported a breakthrough in the development of a next-generation thermochromic window that reduces the need for air conditioning while simultaneously generating electricity. with this advancement, the scientists aim to reduce energy consumption in residential and commercial buildings whose energy expenditure in cooling these spaces off uses 74% of all electricity and 39% of all energy in the united states.

dubbed thermochromic photovoltaic, this technology allows windows to change color to block glare and reduce unwanted solar heating when the glass gets warm on a hot day. to add to this benefit, this color change leads to the formation of a functioning solar cell that generates on-board power. not only would the buildings use less power, but they would also generate it, increasing their contribution to the broader energy grid’s needs. and in terms of aesthetics, the new breakthrough also presents a myriad of colors and a broader range of temperatures, increasing design flexibility for architects and end users.

this research builds upon earlier work at NREL into a thermochromic window that darkened as the sun heated its surface (see graphics illustrating this article). as the window shifted from transparent to tinted, perovskites embedded within the material generated electricity. this first-generation solar window required temperatures between 150 degrees and 175 degrees fahrenheit to switch from transparent to reddish brown. the latest iteration features more colors and works at 95 degrees to 115 degrees fahrenheit, an easily achievable temperature.

the current thermochromic window takes about seven seconds to display its color transformation and returns to its normal transparent state once the humidity is lowered. additional research is planned, including that of covering sunlight into electricity.

project info:

name: thermochromic photovoltaic

developers: U.S. department of energy’s national renewable energy laboratory (NREL)