Scientists have created a yin-like super white paint for Vantablack’s Yang.
Today, ultra black materials can absorb more than 99.96% of sunlight, but this new super white coat can reflect 95.5% of all photons hitting light.
Rather than being warmed up in direct sunlight, objects painted with this new acrylic material can remain cooler than ambient temperatures even under the sun, which could allow for new energy-efficient ways of controlling the temperature inside a building.
The other “heat barrier paint” we currently have can only reflect 80 to 90% of sunlight and cannot achieve temperatures below ambient.
“Developing a subambient radiant cooling solution that provides a convenient single-layer particle matrix paint shape and high reliability is an ongoing work.” Say Xiulin Ruan, mechanical engineer at Purdue University, Indiana.
“This is very important for the widespread application of radiant cooling and for mitigating global warming effects.”
During the summer months, many modern buildings rely on air conditioning units to push the heat inside the building to the outside. This makes the city “with excess heat generated through the intense energy required to achieve cooling.”Heat island“And it makes global warming worse.
Radiant cooling It is a passive technique that reflects the heat of a building into space, but it is much more difficult to achieve than radiant heating.
Since the 1970s, scientists have figured out how to reflect enough sunlight, so passive cooling is more effective than active air conditioners.
Recently, some have even tried to assemble’reverse solar panels’ that can capture some of the heat that goes out at night and convert it into energy.
But for now these are just concepts and it’s unclear whether such a device could really work outside of a simple simulation.
Painting residential and commercial buildings super white could be a more feasible approach, at least in the near future.
The new acrylic paint has a high particle concentration and is made using calcium carbonate fillers of various sizes, which can efficiently scatter all wavelengths of the solar spectrum.
The paint’s matrix has vibrational resonance peaks that allow large amounts of heat to be reflected outward at a much higher rate than other cooling paints.
During a two-day field test in various locations and in various weather conditions, the researchers tested the radiant cooling ability of the paint, and found that the paint can scatter 95.5% of the sunlight, at night 10°C lower than ambient temperature and ambient temperature. It is at least 1.7 ° C lower than. At noon.
Objects covered with calcium carbonate paint maintained a significantly lower temperature in infrared imaging compared to surfaces coated with the same thickness of commercial white paint.
Moreover, this paint is wiped and dried in much the same way, it is wear-resistant, waterproof, and although longer tests are currently underway, it can withstand outdoor weathering for at least 3 weeks.
“Our paints are compatible with the manufacturing process of commercial paints, and the cost may be similar or lower.” Say Luan.
“The key is to ensure the reliability of the paint, making it viable for long-term outdoor applications.”
author say Their paints are “best reported radiative cooling performance”, but while reviewing the results, the other team paper It is claimed that the cooling paint should contain a high concentration of wide bandgap particles.
They also suggest incorporating fluorocarbon-based polymers with high weather resistance.
“Many conventional white paints are designed for durability, but over time the sun’s reflectivity declines.” Explicate.
“Materials such as fluoropolymer-based binders can improve reflectance life and lower average annual costs.”
Creating a single layer paint that can reflect heat directly into space without energy input will be a big win for the climate crisis, as it is usually powered by fossil fuels and can be cooled. Overall impact on global warming.
The new paint still has to go through a few more tests, but it has already been patented. The name has yet to be revealed.
This study is Cell reports physics science.