Posted: January 21, 2010 | |
Nanocoating that acts as efficient heat pump could reduce need for energy-guzzling air conditioning |
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(Nanowerk News) A research by Australian scientists has suggested that a heat pump based on nanoparticles could one day cool buildings without the need for energy-intensive air conditioning. | |
According to a report by ABC News, the research was carried out by Applied physicist Professor Geoff Smith and Dr Angus Gentle of the University of Technology, Sydney. | |
Air conditioning is especially a problem in cities, which have a lot of heat-retaining surfaces, contributing to what is called the "urban heat island effect". | |
Smith and Gentle have created a coating that can be used as an efficient heat pump and reduce the need for energy-guzzling air conditioning. | |
It relies on a phenomenon known as "night sky cooling", in which energy absorbed by surfaces during the day is emitted back into the atmosphere. | |
Smith and Gentle's invention takes advantage of the fact that certain wavelengths of radiation emitted from the Earth are less likely to be reabsorbed by the atmosphere. | |
These wavelengths - between 7.9 and 13 micrometres - are more likely to escape all the way back into space than others. | |
Smith and Gentle have found that a mixture of silicon carbide and silicon dioxide (CO2) nanoparticles emit heat radiation at wavelengths that best take advantage of this atmospheric 'window'. | |
They have found a surface coated with the 50-nanometre sized particles can get down to 15 degrees cooler than ambient temperature in Sydney. | |
According to Smith, the nanoparticle coating could be used to make a kind of reverse solar collector. | |
Air, or water, would flow in channels beneath a plate coated with the nanoparticle mixture. | |
Rather than absorbing the radiation for heating purposes, the set up would emit radiation, cooling air or water that could then be pumped through buildings to cool them. | |
As well as cooling buildings, the technology could also be used as a coating on refrigerators, especially in remote areas. | |
"The technology would mainly work at night, but could sometimes work on the shady side of buildings," Smith said. |
Source: ANI |
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