Thermal behaviour assessment of a novel vertical greenery module system: first results of a long-term monitoring campaign in an outdoor test cell

Abstract

Vertical Greenery Modular Systems (VGMS) are an increasingly widespread building envelope solution aimed at improving the aesthetical quality of both new and existing façades, contemporarily achieving high energy efficiency performance. Within a research project a new prototype of VGMS was developed, designed and tested. An experimental monitoring campaign was carried out on a test cell located in Turin (northern Italy), aimed at assessing both biometric parameters and energy related issues. Two different types of growing media and two plant species, Lonicera nitida L. and Bergenia cordifolia L., have been tested on a south facing lightweight wall. Results have been compared to the same wall without VGMS and plaster finished, in order to characterize the thermal insulation effectiveness in the winter period and the heat gain reduction in the summer period. Measured equivalent thermal transmittance values of the green modular system showed a 40% reduction, when compared to the plastered wall, thus noticeably impacting on the energy crossing the façade during the heating season. Benefits of the VGMS are measured also during the summer season, when the presence of vegetation lowers the outdoor surface temperatures up to 23°C compared to the plastered finishing, with a positive effect on outdoor comfort and urban heat island mitigation. Nevertheless not significant reduction was observed as far as the entering energies are concerned, since the green coverage acts as a thermal buffer and solar radiation is stored and released slowly if compared to the plastered wall.

A novel vertical greenery module system for building envelopes: The results and outcomes of a multidisciplinary research project

“…A multidisciplinary approach has been used, by a mixed work group composed of partners with different skills, to optimise the performance of the VGMS prototypes. The first experimental results, which were only related to thermal aspects, were published in Bianco et al [12]. The entire project is presented in this paper.…”

“…A sub-category of VGS is the vertical greenery modular system (VGMS), where a modular technological box is designed in order to provide a good site for rooting, as well as a suitable amount of water and nutrients for the plants to grow. This kind of technological solution is able to provide different beneficial effects: during the cooling season, thanks to the shading effect of the leaves and the evapotranspiration of the plants, the entering loads are lowered [10], while, during the heating season, it can contribute to reducing heat losses and improving surface thermal resistance, because of the wind reduction in the vicinity of the wall [11,12], to increasing the sound insulation of the wall [13,14] and reducing the environmental impact of the buildings [15][16][17]. At an urban level, VGSs are able to filter pollution [18], to sequester CO2 [19], to reduce urban sound propagation [20][21][22], to give a pleasant aesthetical aspect to a building, to improve the bio-diversity [23] and to mitigate the urban heat island effect (UHI) [24,25].…”

Residential Greenery: State of the Art and Health-Related Ecosystem Services and Disservices in the City of Berlin

“…The possibility of implementing residential greenery, enhancing the supply of ecosystem services and improving the wellbeing of the inhabitants are many. Among the elements that can be implemented, worthy of note are the green walls, which can help to increase the level of biodiversity and reduce the urban heat island effect [52,53]. This improves the aesthetic quality of the residential greenery, encouraging residents to stay longer in the area.…”

Experimental Tests of Thermal Properties Pertaining to Vertical Plant Systems in the Climate of Lower Silesia

“…Temperature analyses in Italy in the winter months showed a reduction of up to 40% in comparison with a plastered wall, which had a noticeable effect on the energy passing through the façade during the heating season. The benefits of using green walls have been noticed during the summer season, when in the presence of vegetation, the surface temperature of the outer wall was reduced down to 23°C, in the case of walls located in Lower Silesia, where the average air temperature behind the panel with vegetation was 21°C (Bianco et al, 2017). Also on the roof of the Hepia School in Geneva, the LEEA Laboratory carried out an experiment using green walls.…”