The scientists of the Stanford University developed a new type of thermal paint that can keep homes and buildings cool in the summer and warm in the winter, significantly reducing energy use and associated costs, as well as greenhouse gas emissions.
According to Stanford researchers, heating and cooling costs account for about 13 percent of global energy use and about 11 percent of greenhouse gas emissions.
The new paints reduced the energy used to heat a home by about 36 percent, in experiments with artificial cold environments, according to a study published today in the Proceedings of the National Academy of Sciences, while the energy needed to cool a home dropped by almost 21 percent in artificial heat conditions.
In simulations of a typical mid-rise apartment building in different climate zones across the United States, with new paint on exterior walls and ceilings, total energy use for heating, ventilating, and air conditioning decreased 7.4 percent over the course of one year.
"Energy and emissions from heating are projected to continue to decline due to improvements in energy efficiency, but air conditioning use is increasing, especially in developing economies in a warming world," said lead author of the study, Yi Cui, a professor of materials science and engineering and of photon science at the SLAC National Accelerator Laboratory.
"For both heating and cooling we must reduce energy and emissions globally to meet our zero emission targets," said Cui, who heads the Precourt Institute for Energy and the Sustainability Accelerator, both within the Stanford's Doerr School of Sustainability.
"Increasing attention is being paid to how to reduce heat exchange between people's living and working spaces and their surroundings, and there is a demand for new materials to improve insulation, such as low-emissivity window films," said the investigator.
The creators highlighted that, currently, low-emissivity paints tend to have a silver or metallic gray color, whose aesthetics limit their use; however, the newly created paints have two separately applied layers: an infrared-reflective lower layer with aluminum flakes, and an infrared-transparent upper layer with inorganic nanoparticles, with a wide color gamut.
It should be noted that the infrared spectrum of sunlight causes 49 percent of the planet's natural heating when absorbed by surfaces, so to keep heat away, paint can be applied to exterior walls and ceilings.
To keep the heat inside, the paints are applied to interior walls where, again, the bottom layer reflects infrared waves that transfer energy through space and are invisible to the human eye.
In addition to houses and buildings, the paints can be applied to improve energy efficiency elsewhere, for example to cover trucks and train carriages used for refrigerated transport, where refrigeration costs can account for up to half of the budget. Of transport.
"Both layers can be sprayed on a variety of surfaces of various shapes and materials, providing an additional thermal barrier in many different situations," concluded Yucan Peng, co-senior author of the study, who completed her PhD in materials science at Stanford in 2020 and she is now a postdoctoral researcher at Stanford's Geballe Laboratory for Advanced Materials.
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