SNF - Heat removal

Heat removal potential in urban configurations measured at high resolution in wind and water tunnels

The air temperatures are normally higher in urban areas compared to rural areas due to the urban heat island effect (UHI). Due to densification and climate change the temperatures in cities will keep on increasing in the future. Due to climate change also the frequency and intensity of heat waves will increase. The urban heat island effect has an impact on comfort and health of the inhabitants of urban areas, and on the energy demand for heating and cooling of buildings. Urban heat island mitigation measures are needed to improve the thermal comfort and to decrease space cooling demands in buildings in summer. Heat can effectively be removed from urban areas by wind. Wind is also important for the removal of pollutants to improve the air quality in cities. Wind flows in urban areas are highly turbulent and form coherent structures. Shear layers are formed at building edges due to flow separation and they interact with the atmospheric boundary layer. Further complexity is induced by buoyancy effects. These complex flow interactions and their impact on urban heat removal are until now not fully understood.

The primary objective of this project is to get insights in the complex flow structures in urban areas and in their impact on the local microclimate. We particularly aim at enhancing the understanding of the influence of buoyancy on urban flows by measuring both forced and mixed convective cases in wind and water tunnels.