GREEN FAÇADES TO INCREASE
ENERGY EFFICIENCY IN BUILDINGS
Ileana Blanco1, Carlo Alberto Campiotti2, Germina Giagnacovo2, Evelia Schettini1*
1. Department of Agricultural and Environmental Science DISAAT – University of Bari, via
Amendola 165/A, 70126 Bari, Italy
2. ENEA - Italian National Agency for New Technologies, Energy and Sustainable Economic
Development - Technical Unit Energy Efficiency - Agriculture Unit, Via Anguillarese, 301,
00123 Rome, Italy
Abstract
The urban heat island effect induces excessive use of air conditioning systems with an
increase of energy consumption for cooling, a raise of peak electricity demand and waste heat
release. It also generates unsuitable outdoor comfort conditions and an increase in pollutants
concentration. The reduction of the solar heat gain, that increases building’s temperature
during the hot season, can contribute to mitigate localised temperature increases. The use of
green roofs and green façades is a sustainable technology for reducing urban air temperature,
buildings surface temperature and heat transfer through the building components. The green
roofs and façades physically intercept and absorb the solar radiation, shading the building
surface from direct sun exposure, provide cooling by promoting evapotranspiration from the
plants and the substrate, provide thermal insulation in cold season, and influence the effect of
the wind on the building. An experimental test was carried out at the University of Bari (Italy,
41 ° 05 'N, 16 ° 53 'E) during summer 2014. A prototype of building in scale was designed.
Three vertical walls were made with perforated bricks, as commonly used in the
Mediterranean area for vertical envelopes of civil construction; each wall was equipped with a
sealed structure on its backside. Two vertical walls were covered with evergreen climbing
plants: one with Pandorea jasminoides, the second with Rhyncospermum jasminoides; the
third wall was kept uncovered and used as control. The climatic parameters measured, by
means of a data logger and several sensors, were: the external air temperature, the solar
radiation incident on the vertical surface of the walls, the wind speed and direction, the
surface temperature of the wall on the inner side and on the side facing the green façade, the
indoor air temperature inside the sealed volume behind each wall. During the experimental
tests it was observed that the diurnal temperatures registered for the control were higher than
the respective temperatures of the green walls with a difference of about 4 °C.
Keywords: urban agriculture, urban heat island, surface temperature, solar radiation
Corresponding author: Evelia Schettini, Department DISAAT University of Bari, Bari, Italy.
Telephone: +39 080 5443060. Email: evelia.schettini@uniba.it