SINGAPORE: Authorities are considering a novel approach to tackling the sweltering urban heat in Singapore: coating buildings with reflective paint to cool urban areas.
The Straits Times reports that this initiative, spearheaded by industrial developer JTC, aims to cool urban areas by up to 2 degrees Celsius. Scheduled to kick off in the third quarter of 2024, the pilot project will cover Bukit Batok and Sin Ming buildings.
The concept is simple yet potentially game-changing: applying a reflective coating to building facades can reduce heat absorption, mitigating the urban heat island effect.
This phenomenon refers to cities’ tendency to retain more heat than rural areas, largely due to the vast expanse of concrete, asphalt, and buildings.
This project was inspired by an earlier experiment conducted by researchers at Nanyang Technological University (NTU) between 2018 and 2019.
In this trial, two industrial buildings and the connecting road were coated with special paint, while adjacent structures served as controls.
The results, published in March 2024 in the journal Sustainable Cities and Society, were promising: the painted environment exhibited temperatures up to 2 degrees Celsius cooler during the hottest part of the day.
In a separate initiative in 2020, NTU conducted tests on the application of cool paint at two Housing Board blocks in Bukit Purmei.
Subsequently, the Housing Development Board (HDB) extended this experimentation to include 130 blocks in Tampines, with the study anticipated to conclude by 2024.
The secret ingredient in the reflective paint is titanium dioxide, a pigment known for its ability to reflect sunlight. This compound, commonly found in sunscreen, forms the backbone of the cooling mechanism.
Associate Professor Wan Man Pun, who leads the NTU team, explains that the paint bounces off sunlight, preventing buildings from absorbing excessive heat.
Barium Sulphate Pigment instead of Titanium Dioxide for more heat reflection
But the innovation doesn’t stop there. Researchers are now formulating a better-performing paint infused with barium sulphate pigment, which can provide greater heat reflection.
This advanced formula, coupled with a polymer binder, ensures that the reflected heat dissipates efficiently, contributing to a more significant cooling effect.
The beauty of this approach lies in its simplicity. Unlike traditional methods, such as incorporating green spaces or water features, which require extensive urban planning, cool paint can be applied directly to existing infrastructure.
As Associate Professor Wan Man Pun, The NTU team lead from the School of Mechanical and Aerospace Engineering, aptly puts it, “The convenience of cool paint is that you don’t need any redevelopment. You just paint on existing infrastructure.”
Other benefits of reflective paint beyond heat reflection
Moreover, the benefits extend beyond mere temperature reduction. Cool paint can also slash energy consumption by minimising heat absorption, particularly in air-conditioned buildings.
This is crucial, considering that the release of waste heat from air conditioners exacerbates the urban heat island effect.
However, the widespread adoption of cool paint may face hurdles, primarily due to cost considerations. While the price difference from conventional paint is evident, proponents argue that the long-term benefits outweigh the initial investment.
Mr Joseph Goh, vice president of the Institution of Engineers, Singapore, suggests a balanced approach, noting that it may be more costly to apply cool paint on pavements than to building facades.
He said, “To encourage wider adoption, it may not be wise to use cool paint on all surfaces due to the high costs.
If there are regulations to deal with urban heat through the use of greenery, shades or cool paint, there may be greater adoption (of these methods) and lower costs due to economies of scale.”
While cool paint presents a promising solution to urban heat, it’s just one piece of the puzzle. Cooling down an entire city requires a multifaceted approach, incorporating various technologies and measures. /TISG
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