In a new study testing, a new kind of reflective white paint on buildings temperatures dropped by 1.7 degrees Celcius compared to their standard counterparts. Moreover, the pain reflected 95,5% of sunlight.
The scientists behind the new reflective paint say they reached this effect by adding particles of calcium carbonate of different sizes. This would help to cut down drastically on airconditioning. Buildings remain one of the largest sources of CO2 emissions. As the planet warms, and the population grows and becomes wealthier, the price for the environment of cooling buildings is expected to rise dramatically in the coming years.
At this moment the lighting, heating, and cooling of all kinds of buildings cause about 28% of the global CO2 emissions. This is in part due to buildings being heated by either fossil fuels or gas. 75% of the energy needed to heat, light, and cool buildings comes from non-renewable sources.
“In one experiment where we put a painted surface outside under direct sunlight, the surface cooled 1.7C below the ambient temperature and during night time it even cooled up to 10C below the ambient temperature,” said Prof Xiulin Ruan, from Purdue University in Indiana, who’s an author on the study. This is a significant amount of cooling power that can offset the majority of the air conditioning needs for typical buildings.”
“Sunlight is a broad spectrum of wavelengths,” said Prof Xiulin Ruan.
“We know that each particle size can only scatter one wavelength effectively so we decided to use different particle sizes to scatter all the wavelengths. This is an important contributor eventually resulting in this very high reflectance.”
It seems likely that the new paint will leave the lab quite soon. The researchers have filed multiple patents and state that there has been a lot of interest from major manufacturers in licensing the paint. Though, there still needs extensive testing to figure out how long-term reliable the paint is.