A Hydroactive Facade for Rainwater Harvesting and Evaporative Cooling: Dynamic Modeling and Simplification for Application in Optimization-based Long-term Building Operation Strategy

Due to population growth, especially in urban areas, demand for residential and commercial space will further drive the construction of high-rise buildings. To counteract negative side effects of the emerging urban heat island (UHI), the facade surfaces can be equipped with adaptive cooling components. Large-scale application of these facades primarily affects the urban microclimate, but as a side effect also the interior of buildings by influencing the heat exchange with the environment. Working towards an optimal operation strategy for outdoor and indoor conditioning, this work develops a model of an adaptive facade with facade-integrated rainwater harvesting and evaporative cooling. Based on mass and enthalpy balances, the dynamic model equations are derived analytically and further simplified to quasi-stationarity. A parameter study will be conducted for the rainwater absorption and evaporation surface as well as the permeability of the facade.