ZEMCH 2015 - International Conference Proceedings | Page 866

Figure 6 shows the daily minimum surface temperature of the external plaster exposed to solar radiation measured during February 2015, i.e. the coldest month of the examined period. The
minimum surface temperature of the control wall was always lower during the coldest hours of
the day than the temperatures recorded in the same hours for the two walls covered with plants.
The differences between the lowest temperatures recorded for the control and for the green wall
ranged from 2.4 to 2.8 °C (Fig. 6).
Collected thermal images of wall surface temperatures (Fig. 3-4) confirmed the surface temperature values of the walls measured using the thermistors and the cooling effect of the vegetation
layer during warm hours.
During hot months in the test period, the presence of the vegetation layer has mitigated the temperature of the external plaster of the walls, in comparison with the control wall. In wintertime
the vegetation layer has increased the insulation performance of the walls. Globally the presence
of the green layer provides the benefit of decreasing the exposure of building envelope to large
temperature fluctuations that can cause its early deterioration.

Conclusions
The experimental tests carried out from August 2014 to February 2015 on vertical greenery systems in a Mediterranean area took into consideration warm and cold periods. The application
of the green vertical walls in order to mitigate the solar radiation effects on the buildings envelopes during warm periods led to lower the external surface daylight temperatures up to 5 °C in
comparison with a wall not covered with plants. During cold periods it kept the external surface
nighttime temperatures up to about 3 °C in nighttime above the surface temperature of the control wall.
Research is continuing with the aim of analyzing the green wall effects during a whole year in
order to evaluate if the positive effect of insulation provided by the green wall is higher than the
negative effect of shading.
Green walls can represent a sustainable solution for new buildings construction and for existing
buildings retrofitting, in order to reduce the energy demands of buildings cooling systems, to
mitigate the urban heat island, and to improve the thermal-energy performance of buildings.
Additionally, the green roofs and walls offer several benefits such as the improvement of the
outdoor thermal comfort and outdoor air quality, improved health and well-being, reduction of
greenhouse gases in atmosphere and noise, improved aesthetical impact and commercial value
of buildings, an increase of urban biodiversity, storm water management.

Acknowledgements
The present work has been carried out under the “Piano triennale 2012-2014 per la Ricerca di Sistema Elettrico Nazionale, progetto C.2 ‘Sviluppo di modelli per la realizzazione di interventi di
efficienza energetica sul patrimonio immobiliare pubblico’, Piano Annuale di Realizzazione (PAR)
2013”, funded by the Italian Ministry of Economic Development.
The data processing and the editorial work must be shared, within the competencies of the research groups, equivalently among the Authors.

864

ZEMCH 2015 | International Conference | Bari - Lecce, Italy