Nanoscientists have discovered ultra-white paint that will keep buildings and roofs cooler and significantly reduce the energy needs for air-conditioning. As a result, the paint can help in reducing global warming as well. This new paint uses radiative cooling, which uses materials that themselves reflect most of the solar heat and whatever heat they receive; they emit it at a high rate.
The solar reflectance, the ratio of solar energy falling and being reflected back, of the material is as high as 98% and the emissivity, the ability to lose heat, is close to 95%, which means it can help painted surfaces cool faster than the existing range. The nanotechnology researchers developed nanoparticle films and nanocomposite paints of Barium Sulphate, the tested material which is also odourless, to conduct the experiment.
Densely filled with concrete buildings and pavements, our cities have become islands of heat. The surfaces in the urban landscapes absorb and retain heat which increases our energy requirements for air conditioning. For instance, if an air-conditioner has to cool a room one degree lower, it would cost about six per cent more of the energy required otherwise. Cooling solutions like radiative cooling technology, which can keep buildings cooler by using efficient materials, can provide sustainable solutions to the cities’ huge energy needs for air conditioning.
“Our paint can help fight against global warming by helping to cool the Earth – that’s the cool point,” said Xiulin Ruan, who is one of the scientists who conducted the research, while talking to the Guardian. Ruan and the other researchers who conducted the study work at the Birch Nanotechnology Centre of Purdue University in the United States. The pain material performs well in reflecting not only the visible sunlight but also the ultraviolet and infrared radiation coming from the sun. This whitest of the white paint can be used in a range of applications such as cars, buildings and in the aerospace industry as well.