New paint can heat and cool buildings reducing energy use

The invention can also reduce carbon emissions and energy costs.
Loukia Papadopoulos
Objects coated with the new paint.jpg
Objects coated with the new paint.

Yucan Peng/Stanford  

Stanford University scientists have conceived of a new kind of paint that can cool homes and other buildings in the summer and warm them up in the winter, resulting in reduced energy costs and less carbon emissions.

This is according to a statement by the institution published last week.

Trials of the invention found that the energy used for heating was reduced by about 36 percent and that of cooling by 21 percent. Furthermore, overall energy use of the buildings declined by 7.4 percent over the course of a year. This is especially useful as climate change causes extreme weather conditions.

A warming world

“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,” said 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.

“For both heating and air conditioning we must reduce energy and emissions globally to meet our zero-emissions goals,” said Cui, who directs the Precourt Institute for Energy and the Sustainability Accelerator, both within the Stanford Doerr School of Sustainability. 

“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.”

This is not the first paint to achieve cooling and heating but current options usually come with a metallic silver or gray color, limiting their applications. The newly invented paints come in a wide range of mat colors that can be applied to buildings in an aesthetically pleasing fashion.

The researchers tested their paints in eight colors: white, blue, red, yellow, green, orange, purple, and dark gray. The results indicated that they were 10 times better than conventional paints in the same colors at reflecting high mid-infrared light.

Better yet, the paints are not reserved for building and can be applied to a variety of objects to enhance both their cooling and heating attributes.

Various shapes and materials

“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, who completed her PhD in materials science at Stanford in 2020 and is now a postdoctoral scholar in Stanford’s Geballe Laboratory for Advanced Materials.

The paints are also water-repellant making them ideal in humid environments. Furthermore, any surface coated with the paints can be cleaned easily with a wet cloth or water flushing.

More experiments also revealed that the paints’ performance and aesthetics were not altered after being exposed to one week of high temperature (176 degrees Fahrenheit), low temperature (-320.5 degrees Fahrenheit), as well as high acidic and low acidic environments. 

“Our team continues to work on refining the paint formulations for practical applications,” said the study’s other co-lead author, Jian-Cheng Lai, a postdoctoral scholar advised by Zhenan Bao, professor of chemical engineering.

 “For example, water-based solutions would be more environmentally friendly than the organic solvents we used. That could facilitate the commercialization of the paints.”