Evaluation of wall surface temperatures in green facades

Green walls can be used to control the building microclimate as passive systems for energy saving. Three vertical walls were built at the University of Bari (Italy). The first wall was covered with Pandorea jasminoides variegated and the second with Rhyncospermum jasminoides; the third wall was kept uncovered as a control. High-definition infrared images were recorded, and several climatic parameters concerning the walls and the ambient conditions were collected during the experimental test. The daylight temperatures observed on the shielded walls during warm days were lower than the respective temperatures of the uncovered wall by up to 9·0°C; the nighttime temperatures observed during cold days were higher than the respective temperatures of the control wall by up to 6·0°C. The effective thermal resistance of the plants was calculated, using experimental data for a whole year; it ranged from 0·07 to 3·61 m² K/W.