AIR conditioning is a transformative technology. It has made the world’s torrid climes pleasanter to live in, and enabled the siesta-free working habits of the temperate regions to move closer to the equator. But cooling buildings takes a lot of energy. Heat must be pumped actively from their interiors to their exteriors. Fully 15% of the electricity used by buildings in the United States is devoted to this task. If an idea dreamed up by Aaswath Raman of Stanford University and his colleagues comes to fruition, that may change. Dr Raman has invented a way to encourage buildings to dump their heat without the need for pumps and compressors. Instead, they simply radiate it into outer space.The idea, described in this week’s Nature, is both cunning and simple. Outer space is very cold (about 3°C above absolute zero) and very big, so it is the perfect heat sink. Earth radiates heat into it all the time. But this is compensated for by the heat the planet receives from the sun. To encourage one part of Earth’s surface (such as an individual building) to cool down, all you need do in principle is...
from The Economist: Science and technology http://ift.tt/11xqxta
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