West Lafayette, Indiana (Associated Press)-A new paint developed by researchers at Purdue University is the coolest-literally.
Dang Xiulin Ruan, A professor of mechanical engineering at the school, and his Graduate students started working on this project seven years ago, and they did not set out to invent a new paint color. Instead, they want to find a way to save energy and deal with climate change. But they found that paint can do this.
However, the effect of this coating goes far beyond setting a world record. It is considered a breakthrough in sustainability that can reduce or even eliminate the need for air conditioning, thereby reducing the energy required to power it.
“The impact of this coating will help alleviate global warming, the urban heat island effect and the power crisis,” said Xiangyu Li, A postdoctoral researcher at MIT, studied for a doctorate in this project. Student in Ruan Lab. “But my favorite part is that it can directly affect people’s electricity bills, which everyone can feel.”
It is not easy to develop the formulation of this coating. This multi-year research is based on an effort to create a cooling coating to replace traditional air conditioners dating back to the 1970s.
The researchers considered more than 100 different materials and narrowed their choices to 10. From there, the lab tested about 50 different formulations for each material.
“I started to pay attention to every white material in my daily life,” exist Say.
At that time, they discovered barium sulfate. The coating is based on two key characteristics: the concentration and size of the barium sulfate compound.
The paint has a very high compound concentration and can also be used to whiten photographic paper and cosmetics. It also contains barium sulfate particles, which have various sizes in the paint.
Dr. Joseph Peoples said that most white paints have only one particle size, which can reflect the visible part of the solar spectrum, but they absorb more ultraviolet and infrared. Candidates from Purdue University’s School of Mechanical Engineering also work in Ruan’s laboratory.
“The biggest difficulty is getting the paint to reflect the entire solar spectrum as much as possible,” said Renmin.
People say that the amount of light scattered by each barium sulfate particle depends on its size. Therefore, having a wider particle size range allows the paint to scatter more of the full spectrum.
Researchers believe that this whitest white paint may be the closest to Vantablack, which is the blackest black paint that can absorb up to 99.9% of visible light. Studies have shown that the paint used in Ruan’s laboratory can reflect up to 98.1% of sunlight. In contrast, the reflectivity of other highly reflective coatings on the market is between 80% and 90%.
Because Ruan’s pigment reflects almost all incident sunlight, it does not absorb any energy. Then it goes one step further and emits thermal energy into outer space outside the earth’s atmosphere, which means it emits more heat than it absorbs.
“Assuming it’s a dry sunny day outside and the temperature is 85 degrees Fahrenheit,” Purdue University’s paint-covered surface “will be around 75 degrees Fahrenheit,” Renmin said. “The paint will cool itself when the temperature is lower than the ambient temperature, creating free refrigeration, and there is no electricity input at all.”
By reducing the surface temperature of a building coated with this white paint, it also reduces the internal temperature of the building. If the building does not heat up due to sunlight, then the need to turn on the air conditioner or completely remove the air conditioner can be reduced.
“If you cover about 1,000 square feet of roof area with this paint, we estimate that you can get 10 kilowatts of cooling power,” Ruan Said in a statement. “This is more powerful than the central air-conditioning used in most homes.”
Although the 98% to 90% difference may not seem large, exist Say that the building used to absorb 10% of the sunlight, but now it only absorbs 2%-“So it actually absorbs five times, which provides the main cooling benefit.”
When most people think of reducing carbon emissions, they think of the transportation sector and industry. However, according to the United Nations Climate Report, buildings generate nearly 40% of global energy-related carbon dioxide emissions each year. The city stated that in Indianapolis, 66% of community greenhouse gas emissions come from buildings. Most of these emissions are the result of building operations, such as cooling and heating.
Therefore, reducing cooling means using less energy from fossil fuels such as coal and natural gas, which may reduce carbon emissions that cause climate change.
“I think the discovery of white paint may be of great significance in the long run,” said Jeff Dukes, executive director of the Climate Change Research Center at Purdue University. “In many parts of the world, we want to cool buildings in comfortable spaces for most of the year or throughout the year, which can mean huge potential energy savings.”
According to Peoples, the whitest paint also helps reduce the urban heat island effect. Urban heat islands are the result of cities replacing natural land cover with pavements, buildings, and other materials that absorb and retain heat. This will increase energy demand, pollution levels and heat-related diseases.
Climate change is causing more frequent and severe heat waves. According to the Duke Center’s research, by the middle of this century, Indiana may still see 30 days above 95 degrees.
The recent United Nations Climate Change Report issued the “Code Red for Mankind” when talking about the climate crisis and emphasized the importance of taking quick action to curb emissions. Dukes said that this paint may just be a tool in the toolbox.
For ordinary Americans, paint can also make a big difference to their pockets. exist Said, because it is essentially creating free air conditioners.
For a single-story house of about 1,000 square feet, painting can save about $1 a day, which could have been spent on air conditioning. It can save about 30 US dollars a month or nearly 360 US dollars a year in electricity bills.
“The advantage of this kind of coating is that it can save electricity bills, and it also contributes to saving the planet.” exist Say, “It’s connected to everyone.”
According to the researchers, this coating can be used in a variety of ways. The most obvious is in commercial and residential buildings, whether on their roofs, facing direct sunlight, or on the side walls.
But the researchers added that it can even be applied to roads or cars to help cool the earth’s surface on a larger scale.
The team has filed a patent application for this coating and is currently passing the necessary tests to bring it to the market on a large scale. Ruan and his The laboratory is working with a commercial company to ensure that the coating meets the reliability requirements of outdoor coatings and can withstand various factors.
There is no timetable when the paint will be on the shelves, exist Said, but it may take several years for customers to buy it at the local hardware store. Purdue’s coatings should be cost-competitive with other outdoor coatings. he Add, and use a similar manufacturing process, so it is not difficult to produce.
“Our goal is if we can bring it to the market, just like buying any other white paint,” exist Say. “The most important way for us to make full use of scientific innovation in this field is to make it available to more and more people.”
Nonetheless, they recognize that getting people to adopt and use white paint will still face some challenges. Especially from a residential perspective, many homeowners may not be used to seeing white walls, or they may want their houses to be different on the street.
“People no longer use white paint everywhere to keep buildings cool,” Dukes said. “So the question is how many people use it?”
The City of Indianapolis said it has ideas on how to increase the adoption of such practices. Morgan Mickelson, executive director of the Office of Sustainability, said the Office of Sustainability is always looking for ways to make better use of the incentives it can use and encourage residents to use these types of materials.
City officials also recently issued a benchmark and transparency ordinance to help improve the energy and water efficiency of Indianapolis buildings. For building owners participating in the plan, they must measure how their buildings use water and energy each year, and then report them annually. With this data, they can work with cities to find ways to reduce emissions.
Mickelson said she believes that this coating may be a key way to achieve this goal when it is available.
“Our built environment is one of the biggest opportunities to significantly reduce greenhouse gas emissions,” she said, adding that the city will try to find a way to use this coating on its own buildings when it is available.
“It’s so exciting to have the whitest white paint from Purdue University,” Mickelson added, “especially as the institution that Indiana University leads such work.”
Source: Indianapolis Star
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