Why not paint them blue?

Photo by Booyia

Last year we wrote a piece about painting your roof white in order to make it more energy efficient. White roofs absorb less heat than dark roofs, so it will help you keep your house cool. It’s even reckoned to reduce peak rooftop temperatures in summer by an average of 43 degrees Fahrenheit (about 24 degrees C) according to a study that came out earlier this year. Now Researchers at Oregon State University have discovered a chemical compound, a “cool blue” pigment that also has notable heat reflecting properties.

Lighter pigments are generally better when it comes to reflecting heat than dark colors. They usually absorb more heat. But some compounds, like this one discovered at Oregon State University, have dark tones but also the ability to reflect heat in the infrared spectrum, which is responsible for most of the heat energy absorbed from sunlight. The scientist came across this ‘cool blue’ by accident while they were doing research on manganese compounds for their electrical properties. The pigment has infrared heat reflectivity of about 40 percent, which is significantly higher than most blue pigments now being used according to professor Subramanian from Oregon State University. Existing blue pigments are found to be toxic, expensive or decay quickly. Going back as far as the times of the Egyptians, the Han dynasty and Mayan cultures people have expiremented with blue pigment. But this one is apparently more durable, safe for the environment and easy to produce. The compound is now being cleared for a patent.

The pigment could be used on the roofs and walls of buildings to help reduce heat absorption with several energy efficiency benefits. In addition to easing the heat island effect in heavily populated areas they think it would lower peak energy demand and and reduce air pollution from power plant emissions. It is less affected by thermal degradation and more aesthetically pleasing than traditional roofing materials colors. Painting your roof white might not be to everyones liking and is not always a possibility due to zoning laws and regulations, so blue could be a good alternative in the nearby future. The university is momentarily looking for liscensing partners.

Via: oregonstate.edu/ua/ncs/archives/2012/jun/new-compound-could-become-%E2%80%9Ccool-blue%E2%80%9D-energy-efficiency-buildings

www.science20.com/news_articles/cool_blue_manganese_compound_has_40_percent_heat_reflectivity-90660

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