Radiative Paint Engineered to Cool Structures


A new radiative cooling paint has reportedly been developed in India to both reduce electricity consumption and offer relief on hot days in buildings.

According to a recent release from the Government of India’s Ministry of Science and Technology, the research was led by Professor Bivas Saha at the Jawaharlal Nehru Centre for Advanced Scientific Research.

Developed from a novel MgO-PVDF polymer nanocomposite, the paint reportedly demonstrates significant cooling capabilities with a high solar reflectivity and infrared thermal emissivity.

The experiment has also found that the surface temperature of a treated paver decreases by approximately 10 degrees Celsius (18 degrees Fahrenheit) under intense sunlight, which is almost double of the reduction that traditional white paints provide, the researchers say.

The scientists developed the paint by using a technique with ultra-white and ultra-emissive magnesium oxide (MgO)-polyvinylidene fluoride (PVDF) nano-composite prepared from materials that are earth abundant, cheap, non-toxic and non-harmful.

Initially, polymer powders were reportedly transformed into a solution using solvent and then, dielectric nanoparticles are dispersed inside the polymer matrix. After this preparation, different spectroscopic techniques were used to characterize the optical properties of the prepared polymer nanocomposite paint.

The optimized MgO-PVDF with dielectric nanoparticles reportedly resulted in large solar reflectance of 96.3% and a record high thermal emission of 98.5% due to MgO bond vibrations, and other stretching or bonding vibrations from the polymer.

The nanocomposite paint also reportedly exhibited water-resistant hydrophobic properties, which can be coated onto pavers, wood sticks and more with uniformity and adhesion.

“Our innovative research has led to the development of a cost-effective and environmentally sustainable paint capable of reducing surface temperatures (including buildings, tiles, pavers, etc.) by over 10 C during hot summer days,” said Saha.

“With the straightforward application of this paint, we envision it offering significant respite during scorching summer days, benefiting both urban and rural areas alike.”

The work was recently published in the publication Advanced Material Technologies. Saha conducted the work in collaboration with researchers Prasanna Das, Sourav Rudra and Krishna Chand Maurya.

Recent Cooling Coating Research

Back in August, a new kind of paint was reportedly developed by Stanford University that can keep buildings cooler in the summer and warmer in the winter, reducing energy use, costs and greenhouse gas emissions.

According to the researchers, while heating and cooling accounts for about 13% of global energy use and about 11% of GHG emissions, the new colorful paints were able to reduce the energy used by approximately 36% in artificial cool conditions and almost 21% in artificial warm conditions.

Additionally, in simulations of a typical mid-rise apartment building with the new paint on the exterior walls and roofs, total energy use declined 7.4% over a year. 

Standford explains that current low-emissivity paints typically have a metallic silver or gray color, limiting use. However, the new paint has two layers applied separately, including: an infrared reflective bottom layer using aluminum flakes; and an ultrathin, infrared transparent upper layer using inorganic nanoparticles that comes in a wide range of colors.

The paint can reportedly be applied to exterior walls and roofs, allowing most of the sun’s infrared light to pass through the colored layer of the paint, reflect off the lower layer and pass back out as light rather than be absorbed as heat.

Alternatively, to keep heat inside, the paints would be applied to interior walls where it would reflect the infrared waves.

According to the release, up to 80% of high mid-infrared light is reflected by the paints. The color layer also reflected some near-infrared light, enhancing the reduction in air conditioning.

The research team reportedly tested their paints in white, blue, red, yellow, green, orange, purple and dark gray. They were 10 times better than conventional paints in the same colors at reflecting high mid-infrared light, the researchers say.

Editor's Note: This article was updated on Nov. 7, 2023, at 9:00 a.m. to accurately reflect the temperature change in degrees Fahrenheit. 


Tagged categories: Asia Pacific; Coating chemistry; Coating Materials - Commercial; Coatings; Coatings Technology; Cool Coatings; Cool walls; EMEA (Europe, Middle East and Africa); Emissivity; Energy efficiency; Environmental Controls; Green coatings; Latin America; North America; Paint; Polymers; Program/Project Management; Research and development; Solar reflectance; Z-Continents

Join the Conversation:

Sign in to our community to add your comments.