Researchers in the US have created a new type of white paint that could potentially reduce the reliance on air conditioning and cool buildings.
The product is capable of reflecting up to 95.5% of sunlight, and reducing temperatures by 1.7C compared to ambient air conditions.
One of the biggest sources of CO2 emissions are buildings, with the World Green Building Council stating 28% of global CO2 is the result of the cooling, heating and lighting of buildings. This is due to the fact that the cooling and heating of buildings is mainly powered by gas, oil and coal, and over the last couple of decades researchers have been trying to find ways to increase the efficiency of cooling and heating.
In the past, multiple reflective paints have been made for the exteriors of offices and homes in order to reduce indoor temperatures and reflect sunlight. However, none of these products have succeeded in reflecting a sufficient amount of sun rays in order to lower building temperatures below that of the ambient conditions.
That is until now, with researchers in the US stating they have developed a white paint with strong cooling properties.
“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.”
High concentrations of calcium carbonate with different sized particles have been stated as being the key component in the paint that makes it so effective.
“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.”
Despite the promising results from studies conducted so far, there is a long way to go before the product is available in stores with it still needing to be tested for long-term efficiency and reliability. Patents have been filed however, and there is strong interest from manufacturers.