What if you could cool buildings without using electricity? charlesj68 brings word of “the development of a plastic film by two professors at the University of Colorado in Boulder that provides a passive cooling effect.” The film contains embedded glass beads that absorb and emit infrared in a wavelength that is not blocked by the atmosphere. Combining this with half-silvering to keep the sun from being the source of infrared absorption on the part of the beads, and you have a way of pumping heat at a claimed rate of 93 watts per square meter. The film is cheap to produce — about 50 cents per square meter — and could create indoor temperatures of 68 degrees when it’s 98.6 outside. “All the work is done by the huge temperature difference, about 290C, between the surface of the Earth and that of outer space, ” reports The Economist. Read more of this story at Slashdot.