Scientists Invent Paint That Could Cut Your Energy Bills

Scientists have invented a paint that could replace air conditioning and heating while cutting energy bills in the process.

The paint, invented by scientists at Stanford University, works by regulating a building's heat—keeping it cooler in the summer and warmer in the winter, a press release on the invention said.

The use of these paints could act as an alternative for air conditioning and heating, which hugely contribute to global greenhouse gas emissions.

A study on the new paints published in Proceedings of the National Academy of Sciences reported that air conditioning and heating contribute to 13 percent of all global energy use. Subsequently, both contribute toward 11 percent of total greenhouse gas emissions.

The use of the new paints however, which come in a variety colors, reduced total energy used for cooling by about 21 percent.

To study the new invention, scientists tested the paint in an artificially warm environment that mimicked apartment buildings across the U.S. When the paint was used on walls and roofs of the simulated apartments, energy use from heating and air conditioning declined by 7.4 percent over a year.

"Energy and emissions from heating are forecast to continue to fall due to energy efficiency gains, but air conditioning use is rising, especially in developing economies in a warming world," the study's senior author, Yi Cui, professor of materials science and engineering, of energy science and engineering, and of photon science at SLAC National Accelerator Laboratory, said in a press release.

Greenhouse gasses are the main cause of climate change worldwide. Climate scientists have warned that if they are not reduced on a global scale immediately, or at least in the coming years, the Earth will reach a point of no return.

"For both heating and air conditioning we must reduce energy and emissions globally to meet our zero-emissions goals," Yi said. "How to reduce heat exchange between human living and work spaces and their surroundings is getting more attention, and new materials for enhanced insulation—like low-emissivity films for windows—are in demand."

Low-emissivity paints already exist but come in silver or gray colors, making them less aesthetically pleasing and therefore less attractive to use.

Stanford's new paints, however, are different colors. To do this, the paints consist of two levels. One layer consists of an infrared reflectives, using aluminum flakes, and the other is ultrathin, infrared and transparent, which allowed scientists to use nanoparticles in a wide range of colors.

The paints were tested in several colors, including white, blue, red, yellow, green, orange, purple and dark gray, the press release reported.

If a user wants to keep heat out, the paint should be used on exterior walls and on roofs because infrared light from the sun will pass through the colored layer and bounce off the lower layer. That prevents the building from absorbing the heat.

To conserve heat, the paint can be used on the interior walls. This then acts in reverse, where the lower layer reflects infrared waves.

The paint will reflect about 80 percent of the high mid-infrared light, Stanford University reported.

Following the tests, scientists found that the new paints were 10 times more effective than others in reflecting infrared light.

These paints can also be used on other surfaces, such as trucks and trains, for the same purpose.

"Both layers can be sprayed onto assorted surfaces of various shapes and materials providing an extra thermal barrier in many different situations," said Yucan Peng, co-lead author of the study.

Following the breakthrough invention, the Stanford University team will continue researching how to refine the paint application.

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