Predictive model of surface temperature difference between green façades and uncovered wall in Mediterranean climatic area

The thermal potential of vertical greenery systems in buildings can be fully explored through modelling. Models support designers in choosing between different technical solutions. This study analyses the cooling effect of two plants suitable for the Mediterranean area. A regression model simulating the difference of the wall external surface temperature between the wall covered with vegetation and an uncovered wall was developed. In order to overcome the gaps in literature, the model was fitted and validated on long period experimental data. It was based only on the use of climatic conditions as input variables, without making assumptions about the plants. Climatic data were grouped in solar radiation slots; the most significant predictors were selected for each slot. The adoption of this method allowed to obtain, during validation, coefficients of determination (R2) higher than 0.95 and low values of the root mean square error (0.4–0.6 °C). It was found that the vegetated walls recorded surface temperatures lower than the uncovered wall up to 7.7 °C in summertime. The results showed that the model developed with a statistical approach can efficiently be used for simulating the thermal effects of a green façade in a similar Mediterranean climate.