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Energy Efficiency thermeleon

Published on October 11th, 2009 | by Susan Kraemer

10

MIT Roof Tiles Save Energy in All Climates

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October 11th, 2009 by
 

A team of students at MIT has just developed a temperature sensitive roof tile that turns black and absorbs heat in cold weather, and turns white, reflecting heat away when it’s hot.

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In cold weather, the polymer stays dissolved and the black backing shows through, but exposed to heat, tiny droplets form and scatter the light back to produce a white appearance. The tiles reflected 80% of the sunlight falling on them when white, and only 30% when black.

The cooling needs would then be reduced 20%.

Dark-roofed houses absorb more heat, requiring more air conditioning use in the summer for cooling, which in turn means using more energy for running air conditioners, which emits more greenhouse gases. Steven Chu at the DOE famously recommends “cool” white roofing for the sunny states – mentioning California, Florida and Georgia. Cool roofs reduce energy costs associated with air conditioning.

There are already special energy efficient elastomeric roof paints, rated by the independent cool roof council through coolroofs.org for how well each one reflects heat. California Energy Commissioner Athur Rosenfeld probably originated the idea to use “white roofs” for sunny climates, where air conditioning costs outpace heating costs for energy use.

In summer, the white roofed house is reflecting heat away. lowering energy costs. But for climates that get both extremes of heat and cold winters, there has not been a solution till now. Their carbon emitting energy use goes up summer and winter.

The MIT team that came up with this tile were the winning competitors in the Making and Designing Materials Engineering Contest (MADMEC) that this year has been focused on energy efficiency. They have the marketing down. They’ve named their reversible black/white tile the Thermeleon, which rhymes with chameleon.

They used a common commercial polymer like that used in hair gels in a water solution, encapsulated between flexible plastic layers with a dark layer at the back.

The materials they used were common and cheap, so commercial viability would not be an issue, though they have more testing to do on durability. The students plan to develop it into a commercial enterprise with a simple white paint that would still have their color changing properties, but can be painted over dark roofs.

Source: MIT

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About the Author

writes at CleanTechnica, CSP-Today, PV-Insider , SmartGridUpdate, and GreenProphet. She has also been published at Ecoseed, NRDC OnEarth, MatterNetwork, Celsius, EnergyNow, and Scientific American. As a former serial entrepreneur in product design, Susan brings an innovator's perspective on inventing a carbon-constrained civilization: If necessity is the mother of invention, solving climate change is the mother of all necessities! As a lover of history and sci-fi, she enjoys chronicling the strange future we are creating in these interesting times.    Follow Susan on Twitter @dotcommodity.



  • http://bestwestroofing.com Green Roofing

    In this blog we find the information about roofing tiles.A roof tile that is sensitive in nature turns black and absorbs heat in cold weather and turns white,reflecting heat away when it’s hot.Great to see you guys helping to promote and inform about it. your blog is very nice and full of information.thanks for taking the time to write.

  • http://www.gonotebook.info matt george

    A good solution to save energy is to use a notebook instead of a desktop computer, like the people describe in this most funniest youtube video:

    http://www.youtube.com/watch?v=X43mAahPifI

  • http://www.gonotebook.info matt george

    A good solution to save energy is to use a notebook instead of a desktop computer, like the people describe in this most funniest youtube video:

    http://www.youtube.com/watch?v=X43mAahPifI

  • Uncle B

    As the American Dream lifestyle fades and a new eco-sensitive, survival mode falls over America, as oil prices and all other prices for that matter rise exponentially and the dollar continues its hysterical, screeching fall to an unfathomable bottom. as cars shrink in size, gain in endurance and highest mileages yet seen, we have to admit paradigm shift of great measures, affecting our very souls! White roofs, black roofs, solar roofs, anything to get off-grid and away from the corporate clutches at our wallets! We need power from the sun, What appears to be very little power today, will in the bottom of the trough of the next cyclic economic downturn will seem a free Godsend, and not a pittance at all! I say, more important than color changing roofing, Solar lighting stored up in batteries by day, feeding LED lights for evening and night time use will be of greatest service and a better investment! So will an edible potato patch over a green lawn, but that’s just what I think.

  • Uncle B

    As the American Dream lifestyle fades and a new eco-sensitive, survival mode falls over America, as oil prices and all other prices for that matter rise exponentially and the dollar continues its hysterical, screeching fall to an unfathomable bottom. as cars shrink in size, gain in endurance and highest mileages yet seen, we have to admit paradigm shift of great measures, affecting our very souls! White roofs, black roofs, solar roofs, anything to get off-grid and away from the corporate clutches at our wallets! We need power from the sun, What appears to be very little power today, will in the bottom of the trough of the next cyclic economic downturn will seem a free Godsend, and not a pittance at all! I say, more important than color changing roofing, Solar lighting stored up in batteries by day, feeding LED lights for evening and night time use will be of greatest service and a better investment! So will an edible potato patch over a green lawn, but that’s just what I think.

  • Uncle B

    As the American Dream lifestyle fades and a new eco-sensitive, survival mode falls over America, as oil prices and all other prices for that matter rise exponentially and the dollar continues its hysterical, screeching fall to an unfathomable bottom. as cars shrink in size, gain in endurance and highest mileages yet seen, we have to admit paradigm shift of great measures, affecting our very souls! White roofs, black roofs, solar roofs, anything to get off-grid and away from the corporate clutches at our wallets! We need power from the sun, What appears to be very little power today, will in the bottom of the trough of the next cyclic economic downturn will seem a free Godsend, and not a pittance at all! I say, more important than color changing roofing, Solar lighting stored up in batteries by day, feeding LED lights for evening and night time use will be of greatest service and a better investment! So will an edible potato patch over a green lawn, but that’s just what I think.

  • MD

    You know my kids have “hot wheels” cars that do similar when exposed to heat and cold – I always wondered why no one attempted to use a similar surface coating on metal roofs.

  • MD

    You know my kids have “hot wheels” cars that do similar when exposed to heat and cold – I always wondered why no one attempted to use a similar surface coating on metal roofs.

  • http://extremegreenvillage.com Bob

    This is interesting, an article saying what a good idea this sunlight reflective/absorptive system is and a reference to coolroofs.org that says the black roofs do not have signifigant heat retention savings.

    So what is the story?

  • http://extremegreenvillage.com Bob

    This is interesting, an article saying what a good idea this sunlight reflective/absorptive system is and a reference to coolroofs.org that says the black roofs do not have signifigant heat retention savings.

    So what is the story?

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