In the face of increasing global warming and urban heat island effects, cooling technologies have become a crucial aspect of modern life. The reliance on active cooling devices such as air conditioners, electric fans, and refrigerators not only consumes enormous amounts of electrical energy but also contributes significantly to greenhouse gas emissions, further exacerbating the problem. To combat these challenges, researchers are developing passive cooling solutions that can help maintain cooler surfaces without the need for electricity. One such innovation is the radiative cooling technology, which has the potential to revolutionize how we keep structures and surfaces cool, while simultaneously reducing energy consumption and environmental impacts.
At the Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR) in Bengaluru, a team of researchers led by Professor Bivas Saha, in collaboration with Prasanna Das, Sourav Rudra, and Krishna Chand Maurya, has unveiled an affordable and environmentally friendly radiative cooling paint. Engineered from a novel MgO-PVDF polymer nanocomposite, this solution-processed paint showcases remarkable cooling properties with high solar reflectivity and infrared thermal emissivity. Their experiments have shown that this innovative paint can reduce the surface temperature of a treated surface, such as pavers, by approximately 10°C under intense sunlight, almost twice the reduction achieved by conventional white paints.
The key to this groundbreaking paint lies in its composition. The researchers used an ultra-white and ultra-emissive magnesium oxide (MgO)-polyvinylidene fluoride (PVDF) nanocomposite made from materials that are abundant, affordable, non-toxic, and environmentally friendly. The process involves transforming polymer powders into a solution using a solvent and dispersing dielectric nanoparticles within the polymer matrix. The optical properties of the resulting polymer nanocomposite paint were characterized using various spectroscopic techniques. The paint’s cooling performance was validated by measuring its temperature under hot sunlight using a thermocouple.
The optimized MgO-PVDF nanocomposite paint exhibited an impressive solar reflectance of 96.3% and a record-high thermal emission of 98.5%. These exceptional properties result from the vibrations of Mg─O bonds and other stretching/bonding vibrations in the polymer. Additionally, the paint is water-resistant and hydrophobic, ensuring it can be applied to various surfaces such as pavers and wood sticks with high uniformity and good adhesion.
Professor Bivas Saha, Associate Professor at the Jawaharlal Nehru Centre for Advanced Scientific Research, stated, “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. With the straightforward application of this paint, we envision it offering significant respite during scorching summer days, benefiting both urban and rural areas alike.”
This promising development, published in Advanced Material Technologies, opens the door for industries to implement radiative cooling paint for building cooling applications. By adopting this innovative paint, the construction industry could significantly reduce its reliance on energy-intensive air conditioning systems, leading to a reduction in associated environmental impacts. The introduction of such eco-friendly and cost-effective cooling solutions is a positive step toward a more sustainable and energy-efficient future.