Scientists in Singapore are pioneering a groundbreaking approach to passive cooling with a newly developed paint designed to significantly enhance building temperature regulation without relying on air conditioning. This innovative paint reflects sunlight and employs a unique mechanism of evaporative cooling, whereby it slowly releases absorbed water to cool surfaces. This mechanism could prove transformative, especially in hot and humid climates like Singapore’s, where traditional cooling methods often fall short. Conventional cooling paints typically function by repelling water, but the novel formulation exhibits the ability to retain moisture, making it suitable for regions susceptible to high humidity.
The concept behind this passive cooling technology focuses on utilizing natural processes to keep surfaces cool. According to material scientist Li Hong, the new paint negates the need for electrical power or mechanical systems to function effectively. Instead, it harnesses the principles of radiative cooling—reflecting sunlight and allowing heat to radiate away from surfaces into the atmosphere. The humidity in places like Singapore can stifle this process, leading to higher surface temperatures. To counter this challenge, researchers Marco Hong and his team from Nanyang Technological University have designed a cement-based formulation that combines three cooling strategies: radiative cooling, evaporative cooling, and solar reflection.
To validate the performance of their new paint, the team conducted tests on three model homes painted with different coatings over two years—one with standard white paint, another with commercial cooling paint utilizing only radiative cooling, and a third coated with their newly developed formulation. While the homes painted with standard and commercial cooling paint faded and yellowed over time, the new paint maintained its whiteness, crucial for ensuring high reflectivity and continued cooling effectiveness. This highlights the material’s superior durability, essential in preserving its functionalities over extended periods.
Crucially, the paint’s porous structure aids in water retention, allowing it to release moisture slowly—akin to how skin releases sweat. This property not only enhances cooling but also promotes energy efficiency; homes coated in this novel paint demonstrated a significant reduction in electricity consumption for air conditioning by 30 to 40 percent compared to homes with other types of paint. This efficiency is critical, as around 60 percent of energy use in buildings globally is attributed to space cooling.
Beyond energy efficiency, the application of this paint could also mitigate urban heat island (UHI) effects—phenomena where urban areas experience higher temperatures than surrounding rural areas due to human activities, infrastructure, and limited vegetation. Coauthor See Wee Koh emphasized the paint’s ability to manage heat emissions better than traditional air conditioning systems, which typically expel warm air into the environment. In contrast, the new paint emits absorbed heat in an invisible form as infrared radiation, effectively reducing localized warming and contributing to cooler urban landscapes in cities like Singapore and other regions facing similar challenges.
Overall, the advent of this innovative cooling paint represents a promising and sustainable solution to combat heating issues in urban settings. By showcasing the potential for significant reductions in energy consumption and mitigating UHI effects, this research could foster a paradigm shift in how buildings are designed and managed in hot climates. The development underscores the need for more energy-efficient technologies to tackle rising global temperatures and enhance urban living conditions effectively.
