Exploring physics of city ventilation and thermal climate by simulation

Abstract

Weather related hazards such as heatwave and urban warming threatens the living habitats of city dwellers. The hotter urban environment has already led to significant health and energy challenges in cities such as Hong Kong. Wind and climate at street level in such a city are affected by those at building microscale, and regional mesoscale. The difficulties of simulating climate and environment at microscales in a city are known. A unified micro- and meso-scale approach is on the horizon. Both field measurement and laboratory models are needed and useful to supplement the simulations In this talk, the speaker will introduce how building and city simulation has enabled us to understand urban heat island circulation (city heat dome), as affected by earth rotation, inversion and light winds, how two or more heat domes merge, how a stronger heat dome enhances foehn winds and contributes to the heatwaves in Hong Kong, and finally how f sea water cooled air condition systems may reduce the peak temperature during urban heatwaves. The latter may serve as an example how the building simulation community can contribute to urban climate control. The speaker advocates a future of transferring knowledge from building simulation to urban climate design, i.e. a city climate can be designed as a building.