Scientists have created an extremely white paint that represents yin in relation to Yang Vantaplak.
While today extremely black materials can absorb more than 99.96% of sunlight, this new ultra-white envelope can reflect 95.5% of all the photons that collide with it.
Instead of warming under direct light, objects coated with the new acrylic material can stay cooler than their ambient temperature even under the sun, which could allow for a new, energy-efficient way to control the indoor temperature.
Our other “heat resistant paints” currently can only reflect 80 to 90 percent of sunlight and cannot achieve temperatures lower than ambient temperatures.
“It is an on-going mission to develop a lower than ambient radiative cooling solution that provides suitable single-layer coating form and high reliability,” Says Xiulin Ruan mechanical engineer at Purdue University in Indiana.
“This is critical to the widespread application of radiative cooling and to mitigate the impact of global warming.”
In the summer, many modern buildings rely on air conditioning units that push heat from inside to outside. This, along with the extra heat generated through the intense energy required to achieve cooling, contributes to transforming cities intoHeat islands“It is exacerbating global warming.
Radiative cooling It is a passive technique that reflects heat from the building into space, but is much more difficult to achieve than radiation heating.
Since the 1970s, scientists have been trying to figure out how to reflect enough sunlight so passive cooling is more effective than an active air conditioner.
Recently, some have even tried to assemble “reverse solar panels”, which can capture some of this outgoing heat and convert it into energy, even at night.
But at the moment these are still just concepts, and it is not clear if these devices can actually operate outside of the simulated range.
Painting residential and commercial buildings super white might be a more feasible approach, at least in the near future.
The new acrylic paint is made using calcium carbonate fillers with high particle concentration and a wide range of sizes, which can efficiently disperse all wavelengths of the solar spectrum.
The paint matrix also has a peak vibration resonance, ensuring that a great deal of heat is reflected outward – at a rate much higher than what other cooling paints can achieve.
During two days of field tests at different locations and under different weather conditions, the researchers tested the radiative cooling capabilities of the coating and found that it can scatter 95.5 percent of sunlight, stay 10 ° C below the ambient temperature at night and at least 1.7 ° C below ambient temperatures. . at noon.
Compared to surfaces coated with the same thickness of commercial white paint, the objects coated with calcium carbonate paint maintained significantly lower temperatures in infrared shots.
What’s more, these paint brushes dry in roughly the same way, are wear-resistant, water-repellent, and can withstand the external weather for at least three weeks, although longer trials are currently being conducted.
“Our paint is compatible with commercial paint manufacturing process, and the cost may be comparable or even lower,” Says Rawan.
“The key is to ensure the coating is reliable so that it is applicable in long-term outdoor applications.”
The Authors Say Their coating is considered to be the “best reported radiative cooling performance”, although they acknowledge that while reviewing their results, another team posted a sheet He argues that the quenching coating should contain high concentrations of broadband gap particles.
They also propose to incorporate fluorocarbon-based polymers, which exhibit high resistance to weathering.
“ Many of the traditional white paints, although designed for durability, experience reduced sun reflection over time, ” He explains.
“Materials such as fluoropolymer based adhesives can enhance the reflection life and thus reduce average annual costs.”
Creating a monolayer coating that can reflect heat directly into space without the need for energy input would be a big win for the climate crisis, as cooling is usually powered by fossil fuels and has Significant overall impact on global warming.
More testing remains to be done on the new paint, but the patents have already been filed. The name has not been disclosed yet.
The study was published in Cell Physical Sciences Reports.