The primary root of Urban Heat Island (UHI) phenomena is urbanization, where natural softscapes are replaced with hard surfaces that absorb and re-radiate thermal energy back into the environment. Asphalt roads and pavements in particular were found to be able to heat up to as high as 60°C, and radiate the excess heat back into environment. This paper highlights the effectiveness and suitability of a dark coloured pavement coating with high albedo, named “PerfectCool”, recently developed by NIPPO Corporation Co. Ltd, Japan Laboratory tests reveal that PerfectCool was able to reflect up to 81% of near infrared red waves, had a low heat conductivity of 0.252 W/mK and had high emissivity value of 0.828. Throughout the duration of the controlled mock-up experiment, PerfectCool consistently recorded lower surface temperatures as compared to concrete slabs with and without conventional paving coating. PerfectCool was able to reduce peak surface temperatures by up to 5°C.
On-site measurements reveal that PerfectCool was able to reduce asphalt surface temperatures to about 38°C. This is a temperature reduction of up to 17°C as compared to a normal asphalt surface without PerfectCool. PerfectCool was able to prevent a built-up of heat within asphalt roads, preventing them from becoming a heat sink, which could prolong the service life of the asphalt surface. This is clearly supported by the low sub-surface temperatures of 34°C, 16°C lower than the asphalt roads. Potential cost savings were also determined through energy simulation using IES(ve). With the application of PefectCool onto pavements surrounding a development, the potential electrical yearly savings of 3.46% can be derived, with a highest possible monthly savings of 4.88%. On a typical hot day, the possible reduction of chiller load can be up to 7.69%.
Wong Chung Wan et al. 2009. A Study on the Effectiveness of Heat Mitigating Pavement Coatings in Singapore. Presented at 2nd International Conference on Countermeasures to Urban Heat Islands. September 19-23, 2009.
Wong Nyuk Hien (National University of Singapore)
Tan Phay Ping (Building Systems and Diagnostics Pte Ltd et al)
Aw Zhi Wei Aloysius (Building Systems and Diagnostics Pte Ltd et al)
Publication Date: September 2009