Impact of evapotranspiration on urban microclimate



Type. ETH internal research project

Funding. This PhD project is funded by the Chair of Building Physics of ETH Zurich.

Duration. 3 years (2015-2018)

Collaborations. -

ContactThijs Defraeye.

StaffLento Manickathan (PhD).

Project background

Vegetation in urban environments is increasingly being utilized to mitigate the Urban Heat Island (UHI) effect. Vegetation has several positive effects in cities. The foliage of the tree intercepts the solar radiation and provides shading to urban surfaces. The photosynthesis removes CO2 from the air and releases O2 and water vapor. The plant leaves extract heat from the surrounding air for the evapotranspiration process. The combination of all these effects results in a decrease in the air temperature in cities and also improves air quality. However, trees can also obstruct air flow, having a negative effect on the ventilation in cities. The project focuses on predicting the UHI mitigation potential of vegetation and its influence on the flow in the urban microclimate using numerical and experimental investigations. The numerical model considers vegetation as a porous medium in an OpenFOAM CFD model. The experimental studies consist of wind tunnel experiments in our atmospheric boundary layer wind tunnel, to study the flow around vegetation, and refractive index-matching tunnel experiments to study the flow inside transparent vegetation models. Ultimately, the research will support the design of UHI mitigation strategies based on a better use of vegetation in cities.

Funding agency:


PhD Student

Lento Manickathan