Heat Fluxes in a Green Façade System: Mathematical Relations and an Experimental Case

The need of greater environmental sustainability in today’s living contexts can be significantly coped through the introduction of green infrastructures. Their benefits concern improvement of climate and comfort conditions. Among green infrastructures, vertical greenery systems, applied to buildings, contribute to the energy efficiency of buildings and to the improvement of outdoor and indoor microclimatic conditions. Green facades, a typology of vertical greenings, allow a considerable energy saving for air conditioning, by reducing the surfaces temperature of buildings and increasing the envelope thermal insulation. A realistic description of the functioning of green facades is essential to comprehend the real extent of their advantages. This paper aims to provide a first answer to the need of energy simulation models for green facades’ thermal behavior. The paper proposes a theoretical and an experimental approach. The main heat fluxes involved into the green facade system are investigated and described, by resorting to a schematic representation. The defined mathematical relations are applied to data collected during an experiment on a green facade conducted at the University of Bari. This work represents a contribution to the development of a model to forecast the thermal behavior of green facades and of the microclimate of buildings equipped with them.