Urban road and pavement solar collector system for heat island mitigation: assessing the beneficial impact on outdoor temperature

Road renewable energy system has raised much attention from both industrial and academic research on how abundant solar radiation absorbed by road surfaces can be collected while reducing the impact of high surface temperature towards urban environment. Cities consume about 3% of total global land mass with road and parking lots consuming around 35 to 50% of land use footprint. These urban road networks permit the dynamic movement of human activities and physical development of the cities. Remarkably, researches have given much spaces to explore on how roads can contribute to make cities more sustainable. Therefore, ideas on road renewable energy system have surfaced to its audiences. The heat island effect has been reported to raise temperature up to 12 degrees C in urban areas which affects building cooling energy load and simultaneously the people comfort. High discomfort can lead to high energy and cost utilisation, which further worsens the issue. This study assessed the beneficial impacts of urban road pavement solar collector towards reducing outdoor temperature by carrying out de-coupled numerical modelling of an urban canyon model integrated with the pavement solar collector in ANSYS FLUENT, validated with experimental data. Numerical results showed up to 4.67 degrees C air temperature reduction and up to 27.0 % surface temperature reduction after the U-RPSC application. When applying to street canyon with different heights, the concern was highlighted on the system performance in reducing potential UHI effect in deeper canyon during less windy condition and during the night-time. The study also presents the experimental work on the performance of a laboratory-scale U-RPSC system.