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Modern architectural concept of “vertical forest” boosts the tendency of including permeable and green spaces in buildings and its surroundings. However, whilst green spaces generally make buildings and cities more ecofriendly, it is insufficiently known to which extent the surrounding environment and the vegetation may positively or negatively influence the pedestrian-level wind comfort quality of buildings amidst historical and well-settled urban layouts. This was the scope of the present study for which wind-tunnel (WT) testing and 3D RANS simulations were performed on two facing towers in Medellin (Colombia), in order to (i) investigate the wind field and the pedestrian-level wind comfort around the towers; (ii) to compare the performance of WT and 3D RANS for wind comfort analysis; (iii) to evaluate the impact of the environment surrounding the two towers and (iv) the mitigation effects of vegetation on wind comfort. WT tests were performed on a scaled model (1:250) without surrounding, for 12 wind directions and 3 sets of measurement positions. The same case study without (i.e. CFDs) and with (i.e. CFDd) surrounding environment was simulated by 3D RANS. Next, an implemented CFDd case including vegetation (i.e., CFDd-V) was simulated for three LAD values. Overall, the surrounding had a significant impact on wind comfort assessment. The CFDd case showed a better-quality class than WT and CFDs. The CFDs and WT case showed a satisfactory agreement and the similar comfort quality class. The vegetation provided a remarkable improvement of comfort quality class mainly for set 1 and 2.

Urban greening provides a wide range of ecosystem services to address the main challenges of urban areas, e.g., carbon sequestration, evapotranspiration and shade, thermal insulation, and pollution control. This study evaluates the environmental sustainability of a vertical greening system (VGS) built in 2014 in Italy, for which extensive monitoring activities were implemented. The life-cycle assessment methodology was applied to quantify the water–energy–climate nexus of the VGS for 1 m2 of the building’s wall surface. Six different scenarios were modelled according to three different end-of-life scenarios and two different useful lifetime scenarios (10 and 25 years). The environmental impact of global-warming potential and generated energy consumption during the use phase in the VGS scenarios were reduced by 56% in relation to the baseline scenario (wall without VGS), and showed improved environmental performance throughout the complete life cycle. However, the water-scarcity index (WSI) of the VGS scenarios increased by 42%. This study confirms that the installation of VGSs offers a relevant environmental benefit in terms of greenhouse-gas emissions and energy consumption, however, increased water consumption in the use phase may limit the large-scale application of VGSs.

Vertical greening systems and green roofs provide ecosystem services in the urban context. Despite the important benefits they provide, economic (initial and maintenance costs) and environmental issues may limit the widespread diffusion of these greening systems. Mosses can be a low-cost and low-maintenance alternative green envelope for large-scale application on existing urban and industrial buildings thanks to their low requirements in terms of growing substrates, low amount of water and nutrients needed, and high desiccation tolerance. The study assesses the’ growing ability of mosses on building materials and low-cost materials, by means of growing tests performed under controlled environmental conditions on horizontal and vertical surfaces. Moss growth depends mainly on the physical characteristics of the materials, although an acidic moss mixture improves species richness. Results show different surface coverage: capillary matting > cement plaster > lime plaster > terracotta brick > slate > quartzite. The water retention capacity and its homogeneous distribution on the growing surface are the limiting factors for moss growth.

In Europe, buildings are responsible for 40% of the energy consumption and 36% of the CO2 emissions. Space heating largely contributes to these energy and climate impacts. Passive solar heating systems, as sunspaces, can contribute to increase solar heat gains, reducing space heating energy demand and the related use of fossil fuels. Careful design and local climatic considerations are essential to optimize the performance of sunspaces. In this study experimental field monitoring, dynamic modelling and steady-state methods are applied to analyse the thermal behaviour of an attached sunspace in an Italian existing building, as well as its potential contribution to the building’s energy balance. Design modifications for improved thermal performance of the sunspace are investigated. The results show overall agreement between the dynamic modellings and experimental monitoring of the sunspace and indicate that the sunspace’s indoor air temperature and hence solar energy gains are significantly increased with the design modifications, in contrast to the existing configuration. Maximum temperatures between 44 and 48 °C were observed for the existing and a modified alternative of the analysed sunspace. The dynamic simulation model and design modifications presented in this study can serve as basis for assessment and optimal configurations of sunspaces in their design stage.