Studying the potential of energy saving through vertical greenery systems : Using EnergyPlus simulation program

Vertical Greenery Systems (VGS) are upcoming facade cladding fixtures which restore the connection between the city and nature. They are capable of providing thermal benefits to the building. The objective of this study is to explore the impact of VGS on building energy performance. This study simulates thermal effect of VGS using a mathematical model based on heat balance principle of the foliage layer and soil later, which is then integrated into one of the widely accepted building simulation program, EnergyPlus. The integrated VGS model is validated against two reported experimental studies, and show good agreement. Validation results show that integrated VGS model satisfactorily predict the effect of VGS on indoor air temperature and exterior and interior surface temperature of facades with VGS. The integrated VGS model is then used to assess the impact of VGS on building energy performance in warm temperature climates. Simulations have shown that in hot summer days, VGS leads to reduce exterior surface temperature of building facades, maximum of 26 °C. The annual cooling energy consumption is reduced by 3% for warm temperature climates. However, during the winter season insulation effect of VGS cause increase in heating demand of the building. Simulations suggest that, passive energy benefits of VGS are promising during summer periods, whereas it may disadvantageous during winter periods. However, in warm temperature climates, VGS still able to provide net passive energy benefits to the building.