Simulating the impact of ground-based façade greenery design on indoor heat stress reduction

Vertical greenery (VG) reduces the indoor heat hazard. To take advantage of their cooling effects, the underlying key design factors have to be understood. However, the influence of plant species, building type, and VG design on the thermal advantages has received limited attention in current literature.
Therefore, heat fluxes and temperature profiles for different ground based VG designs in the temperate climate of Berlin, Germany, were analysed using a process-based model. Indoor temperature profiles were integrated, assuming that air conditioning (AC) had been installed. Cooling effects have been simulated for six parameterised plant species of varying ages, across three different building types, and alternated air gap and crop thickness.
The results were compared, quantifying the cooling potential and the possible energy savings. They differ between plant species and building types. The diurnal variation of the indoor temperature resulted in maximum savings during the night. Fallopia baldschuanica showed the highest energy savings of approximately 23%. Thereby, it was multiple times more energy efficient than a Humulus lupulus.
This illustrates the significance of selecting the appropriate VG plant species. Considering factors such as growth rates and potential harm to buildings, VG can be strategically optimzed.