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Simulation and experimental investigation of the indirect green façade (IGF) impact on thermal behaviour of buildings is presented in the paper. The study was conducted in Punat, Krk, Croatia, in the summer of 2018. The IGF reduced the incident solar radiation by up to 505 W/m2 and façade temperatures by up to 13.5 K. Experimental results were used to simulate the indoor thermal comfort of a simple building model. When IGF was positioned across the entire sun-exposed wall, an average decrease of operative temperature was up to 6 K for a new house and up to 5 K for a traditional stone house.

The Urban Heat Island (UHI) caused by building densification greatly impacts the sustainability of urban residents and the environment. Therefore, it is necessary to utilize the envelope space of buildings for green retrofitting so that they can contribute to mitigating the UHI effect. In particular, green retrofitting of existing and historic buildings has become an effective means to improve the resilience of cities in the modernization process. In this study, Vertical Greenery Systems (VGS) were proposed for traditional commercial and residential buildings in Guangzhou, China. Digital Twin (DT) technology was applied to simulate the VGS construction method and irrigation to visualize the process of VGS construction for old commercial and residential buildings. In addition, the building heat and cooling consumption of the three-dimensional greening of the storage room on the ground floor of the arcade-housing and the living room on the top floor were analyzed according to the thermal parameters of different vertical greening types and different material facades. Finally, the modification of the west and south walls as a greening system was identified as the best energy-saving solution, and this finding provided reasonable theoretical support for the energy-saving design of the three-dimensional greening building of the arched house on South Street, a historic building with a combination of commercial and residential buildings.

Research has shown the environmental benefits of green envelopes, as well as performance in terms of energy efficiency. To date, there is no analysis of the economic sustainability of these systems, which has allowed the realization of a few, albeit very well known, examples. The research has identified a green modular system integrated into the building envelope, designed to facilitate installation and maintenance, with competitive performance compared to other existing solutions; a system that wants to improve performance and flexibility of vertical applications, experimented on buildings, on the market, and able to adapt, above all, to the needs of the building process. It is important to distinguish architectural aesthetic requirements from those of the building process; the former aim to have an authentic vertical garden, with different kinds of plants where nature dictates the rules, the latter aims to achieve the economic sustainability of vertical greenery systems. This paper provides an analysis of a technique based on the installation of plant bearing modular panels with turf on substructures also provided with a micro-irrigation system, which allows the construction of a modular coating, characterized by reduced thickness, that can also be integrated with other materials; installation is quick and simple, since the panel comes perfectly planted on site. In addition to that it allows, from a botanical point of view, resorting to types of grass selected with a view to climate, exposure, environmental adaptability, color and shape. A comparative analysis of this green façade is also presented compared to other existing case studies, from a constructive and managerial point of view, highlighting both its economic and architectural advantages.

Nature-based solutions applied to the building skin, such as green roofs and vertical greenery systems, are standing out as the most promising by contributing with thermal improvements at building scale. From previous research done by GREiA research group at the University of Lleida (Spain), energy savings up to 58% were obtained by implementing vertical greenery systems on external building walls for cooling purposes. However, since there exist other passive and active energy saving technologies in the literature review that were limited their cooling and heating capacity after implementing internal heat loads, new experimental tests for two different vertical greenery systems simulating the heat loads in both, summer and winter were conducted in this research. Additionally, these experiments also improve the scarce and controversial literature for winter conditions. The results demonstrated that considering internal loads in experimental investigations is crucial for the results of the effectiveness of the green walls and green facades. The energy savings of VGS were reduced between 22.5% and 26.7% because of the internal loads for cooling purposes, and increased about 3.6% and 3.1% for heating.

During the last decade, vertical greenery systems are increasing their presence in building designs, providing several urban ecosystem services. One of them is the potential to provide energy savings in buildings, which develops an important role, however, data about its performance during winter periods is still scarce. Therefore, the main objective of this paper is to compare at real scale the thermal performance of two different vertical greenery systems implemented in experimental houses-like cubicles for both cooling and heating periods. A double-skin green facade has been installed in the first cubicle that uses deciduous creeper plants, while the second one is designed with green walls made with evergreen species. Finally, a third identical cubicle without any green coverage is used as reference. Two different types of experiments have been carried out to test the performance of the house like-cubicles. One consists of controlling the internal ambient temperature providing heating or cooling to maintain the desired comfort conditions. On the other hand, to study the thermal response of the construction system, the heating, ventilation and air conditioning system was disconnected and the cubicles were tested under free floating condition. First results showed a high potential for energy savings during cooling season for green wall (58.9%) and double-skin green facade (33.8%) in comparison to the reference system. On the other hand, for heating periods no extra energy consumption was observed for evergreen system. The work partially funded by the Spanish government (ENE2015-64117-C5-1-R (MINECO/FEDER), ENE2015-64117-C5-3-R (MINECO/FEDER) and ULLE10-4E-1305) in collaboration with the company Buresinnova S.A (C/Saragossa, 95 Entsol 3a, 08006 BARCELONA). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123) and to the city hall of Puigverd de Lleida. This study has received funding from the European Commission Seventh Framework Programme (FP/2007–2013) under Grant agreement Nº PIRSES-GA-2013-610692 (INNOSTORAGE) and from European Union's Horizon 2020 research and innovation programme under grant agreement Nº 657466 (INPATH-TES). Alvaro de Gracia would like to thank Ministerio de Economia y Competitividad de España for Grant Juan de la Cierva, FJCI-2014-19940. Julià Coma would like to thank the Departament d'Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship.

Vertical Greenery Systems (VGS) are promising contemporary Green Infrastructure which contribute to the provision of several ecosystem services both at building and urban scales. Among others, the building acoustic insulation and the urban noise reduction could be considered. Traditionally vegetation has been used to acoustically insulate urban areas, especially from the traffic noise. Now, with the introduction of vegetation in buildings, through the VGS, it is necessary to provide experimental data on its operation as acoustic insulation tool in the built environment. In this study the acoustic insulation capacity of two VGS was conducted through in situ measurements according to the UNE-EN ISO 140-5 standard. From the results, it was observed that a thin layer of vegetation (20–30 cm) was able to provide an increase in the sound insulation of 1 dB for traffic noise (in both cases, Green Wall and Green Facade), and an insulation increase between 2 dB (Green Wall) and 3 dB (Green Facade) for a pink noise. In addition to the vegetation contribution to sound insulation, the influence of other factors such as the mass factor (thickness, density and composition of the substrate layer) and type of modular unit of cultivation, the impenetrability (sealing joints between modules) and structural insulation (support structure) must be taken into account for further studies. The work was partially funded by the Spanish government (ENE2011-28269-C03-02, and ULLE10-4E-1305), in collaboration with the company Buresinnova S.A (C/ Saragossa, 95 Entsol 3ª, 08006 BARCELONA). Moreover, the research leading to these results has received funding from the Eurpean Commission Seventh Framework Programm (FP/2007–2013) under Grant agreement No. PIRSES-GA-2013-610692 (INNOSTORAGE) and from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 657466 (INPATH-TES). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123), to the City Hall of Puigverd de Lleida, and to Gestión Medioambiental de Neumáticos S.L. and Flag Soprema S.L.U. companies. Alvaro de Gracia would like to thank Education Ministry of Chile for Grant PMI ANT1201. Finally, Julià Coma wants to thank the Departament d’Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya for his research fellowship.

Vertical greenery systems (VGS) are effective at solving urban heat. They can absorb noise pollution and dust, and, aesthetically, they are positively perceived. Systems using hydroponic irrigation and nutrition, in combination with mineral wool as a base, are light and effective (they are able to hold water, with a high percentage of air, and a good mechanical structure to hold the plant stable). However, the functionality of a system can be compromised if the water supply is depleted or the irrigation system fails. This deficiency can be partially remedied if a certain amount of biochar or a suitable organic fertilizer is also a part of the system. The research task consisted of verifying this assumption and determining the effective amount of the biochar. Samples with different amounts of biochar were examined under the same temperature and humidity conditions, extended drying times, additional costs, and safety tank size savings were found. Subsequently, the effective amount of the biochar was determined by the Data Envelopment Analysis (DEA) method. It has been experimentally verified that biochar has a positive effect and prolongs the drying time, the additional costs are almost offset by the benefits. It should be noted that the results are valid for central Europe, and may be modified for different climate and economic zones.