Numerical simulation for analyzing the thermal improving effect of evaporative cooling urban surfaces on the urban built environment

Abstract This paper presents a numerical simulation method for analyzing the thermal improving effect of urban surfaces (pavement and building surfaces) with evaporative cooling effect on the urban built environment. The numerical models for simulating the cooling effects of these cooling surfaces were proposed after analyzing the experimental data. The surface wet condition of the moist pavement can be modeled as a function of the pavement water content. The cool building surface is coated with photocatalyst (TiO2) and sprinkled with water in order to cool external surfaces of the building. During sprinkling, the wetted building surface can be modeled to be covered with a free water surface because the TiO2-coated surface can be completely covered with a thin film of water. The simulation algorithms for the two cooling strategies were integrated into a 3D-CAD-based thermal simulation tool. The simulated surface temperature agrees well with the measured result for the cool pavement. As a case study, the cooling effects of these cooling strategies applied to an urban area were simulated and quantified in terms of surface temperature reduction, mean radiant temperature (MRT) and heat island potential (HIP). As a result, the thermal improving effect can be visualized on 3D-CAD models for the analyzed urban block.

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