Towards the urban climate modeling of the Kent Ridge campus

The Campus Sustainability Roadmap 2030 is the National University of Singapore initiative that includes Carbon Neutral NUS, Cool NUS, Zero Waste NUS and Campus in a Tropical Rainforest. The roadmap covers climate mitigation, adaptation, resource efficiency and behavioural change for sustainability. The CoolNUS – BEAM (Baseline-Evaluating-Action-Monitoring) has a significant role through climate sensing to monitor the current condition so mitigation strategies can be administered effectively. Climate simulations are done to validate with the measured data so that the same method can be applied for future masterplans with new or refurbished buildings.

In the realm of urban climate simulation, the most validated 3D CFD solver today is urbanMicroclimateFoam, which runs under the openFOAM.org version 8 framework. Therefore, there is intention to open the workflow so it will not be restricted to a single method of mesher and solver workflow. A stable mesher running under HELYX is selected as the preprocessing for the solver. This ensures that the mesh quality will not contribute to the instability of the solver later down the road. The HELYX mesher is not open-source and therefore, there is a validation required with other meshers in the market, including those under the OpenFOAM family it originates from.

The CFD with solar radiation simulation is done to validate with the measured data of the weather stations in campus. It can also be used to simulate mitigation strategies which include solar photovoltaics, vegetation shading and evapotranspiration, cool paint, and solar film. It acts as a foundation for the future masterplan studies to deal with what-if scenarios. The results can also be used for the walkability agent-based modelling to study the viability of policies such as closing a vehicular road for pedestrian linkage as well as the overall pedestrian thermal comfort route choices in campus with shading impact.