Evaluating the Effects of Façade Greening on Human Bioclimate in a Complex Urban Environment

The evaluation of the effectiveness of countermeasures for a reduction of urban heat stress, such as facade greening, is challenging due to lacking transferability of results from one location to another. Furthermore, complex variables such as the mean radiant temperature are necessary to assess outdoor human bioclimate. We observed in front of a building facade in Berlin, Germany, which is half-greened while the other part is bare. was reduced (mean 2 K) in front of the greened compared to the bare facade. To overcome observational shortcomings, we applied the microscale models ENVI-met, RayMan, and SOLWEIG. We evaluated these models based on observations. Our results show that (MD = −1.93 K) and downward short-wave radiation (MD = 14.39 W/m2) were sufficiently simulated in contrast to upward short-wave and long-wave radiation. Finally, we compare the simulated reduction of with the observed one in front of the facade greening, showing that the models were not able to simulate the effects of facade greening with the applied settings. Our results reveal that facade greening contributes only slightly to a reduction of heat stress in front of building facades.

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