Self-cooling windows let in sunlight without the heat

Microfluidic circulatory system embedded in windows may help reduce air-conditioning costs. Sun-drenched rooms make for happy residents, but large glass windows also bring higher air-conditioning bills. Now a bioinspired microfluidic circulatory system for windows developed by researchers at Harvard University could save energy and cut cooling costs dramatically-while letting in just as much sunlight. The same circulatory system could also cool rooftop solar panels, allowing them to generate electricity more efficiently, the researchers report in the July 29 online edition of Solar Energy Materials and Solar Cells . The circulatory system functions like those of living animals, including humans, which contain an extensive network of tiny blood vessels near the surface of the skin that dilate when we are hot. This allows more blood to circulate, which promotes heat transfer through our skin to the surrounding air. Similarly, the new window-cooling system contains an extensive network of ultrathin channels near the "skin" of the window-the pane-through which water can be pumped when the window is hot.