Vertical greening systems evaporation measurements: does plant species influence cooling performances?

Vertical greening systems (VGS) can increase the energy performances of building envelopes, while providing several environmental and ecological benefits in dense urban areas. In 10 November 2014, the first vertical greening system in the city of Genoa (Italy) was installed on the south facade of a public institution office building, as pilot project aimed at monitoring environmental effects and energy performances. With the aim to evaluate the cooling performances of some of the different plant species and of the living wall system used 15 for the facade, an experimental site was set-up. It consists of five living wall panels: (1) bare, (2) planted with Cistus Jessami beauty, (3) planted with Phlomis fruticose, (4) planted with Hedera helix, (5) planted with Rhincosperma jasminoides and of four pots (9 cm) planted with the same plant species. Measurements were carried out three times per day in 20 the months of July and September 2015. The data collected, elaborated by means of a statistical analysis, show the amount of water evaporated by the panels and the pots, demonstrating that the living wall panels’ behaviour is different compared to the pots’ behaviour and that the performances are different when comparing night and day behaviour.