Vertical Greening Systems Research Articles

Effectiveness of a dynamic living wall system of plants on indoor thermal environment in summer - an experimental study

Optimizing vertical greening systems to reduce their negative impact on buildings is important to reduce energy consumption. To reduce the long-term effects of fixed living plant walls on building facades, this study proposes an optimization scheme for dynamic living plant walls (DLWS). By combining dynamic building facades with living plant walls, this study analyzes the effectiveness of DLWS, fixed living plant walls (LWS), and dynamic shading sails (DSS) in regulating indoor temperature and humidity through controlled experiments. The results showed that DLWS and LWS had the same effect on cooling, reducing the average indoor temperature by 3.6°C during the daytime. Further, DLWS was able to increase the indoor air humidity within the appropriate range, which was lower than the LWS humidity by 6.9 RH. DLWS had a better cooling effect compared to DSS, and DLWS can reduce the indoor temperature by 2.7. The results authenticate the performance advantages and the possibility of applying dynamic plant living walls in practice.

Fine dust collection capacity of a moss greening system for the building envelope: An experimental approach

Air pollution is one of the most impactful environmental issues worldwide in terms of mortality. Numerous studies have assessed the benefits of vertical greening systems within urban areas for mitigating air pollution, but their widespread adoption is limited by high costs and maintenance requirements. The current study assesses the air pollution mitigation capacity within urban areas of three moss species: Barbula unguiculata, Grimmia pulvinata and Homalothecium sericeum, used in the moss envelope system called MosSkin. Following a three-months exposure of the three moss species samples in a highly trafficked area, phyllids were analysed with Field Emission Scan Electron microscopy to quantify number, dimension, and nature of particle deposition on leaves on their different portions (base, centre, apex). The moss species chosen collected up to 45,580 particles per mm2 with the trend H. sericeum ≥ G. pulvinata > B. unguiculata, showing a similar tendency in terms of classes and order of magnitudes. However, specific higher affinities for PM fractions 2–7.5 μm were shown by G. pulvinata. The PMx collection can be related to species-specific shape of leaves within stems, and it depends on the leaf portions (highest capture in apex), 45–55 % consisting of PM0.5 μm, indicating a significant collecting capacity of such fractions.

Consolidating building greening: Integrating mobile modular vertical greening systems into prefabricated building

Vertical greening systems increase green plant coverage within built environments, enhancing urban air quality while reducing building energy consumption. But they encounter challenges related to intensive maintenance and significant costs. As a mainstream future building form, the characteristics of modularization and factory customization inherent in prefabricated buildings can effectively address the demands of vertical greening system. This study employs structural equation model and cloud model to examine the feasibility of integrating mobile modular vertical greening system into prefabricated structures, based on a survey of 403 respondents in Shandong Province, China. The study highlights the supportive roles and mediating effects of two maintenance management measures. It confirms the strong correlations between cost control strategies and the successful integration of mobile modular vertical greening system into prefabricated building. The results indicate that integrating intelligent technology and plant-microalgae combined systems are essential exogenous and endogenous maintenance management strategies. They exert a positive influence on prefabricated modular vertical greening systems. A positive interconnection exists between integrating intelligent technology and the plant-microalgae combined system. Carbon credit trading incentive proves more advantageous in reducing mobile modular vertical greening system costs. Plant-microalgae combined system playing a partial mediating role. Although crowdfunding-community participation does not significantly reduce the costs of mobile modular vertical greening system, integrated intelligent technology mediates this relationship. This highlights the indirect role of crowdfunding-community participation in facilitating cost control for these systems.

Vertical Green Wall Systems for Rainwater and Sewage Treatment

Rainwater and sewage are important pollution sources for surface water bodies. Vertical greening systems (VGSs) are extensively employed for these wastewater treatments due to the green and sustainable characteristics, as well as their high-efficiency in pollutant (organic matter, nitrogen, and phosphorus) removal. At present, more and more VGSs are designed with green buildings, serving city ecosystems. This study provides an overview of different kinds of VGSs for rain and sewage treatment, emphasizing their types, design, mechanisms, selection of plants, and growth substrate. Plants play a crucial role in pollutant removal, and different plants usually obtain different efficiencies of water treatment. Climbing plants and ornamental plants with fast growth rates are priority selections for VGSs, including Canna lilies, Jasmine, Grape vine, Boston ivy, Pittosporum tobira, Pelargonium australe, Mentha aquatica, and Lythrum salicaria. The substrate is the most critical part of the VGS, which plays an important role in regulating water flow, supporting plant growth, promoting biofilm growth, filtering pollutants, and adsorbing nutrients. The single substrate either has a blockage problem or has a short holding time. Therefore, a number of studies have mixed the substrates and integrated the advantages of the substrates to form a complementary effect, thereby improving the overall purification efficiency and stability. Novel substrates (sand, spent coffee grounds, date seeds, coffee grinds, reed-based, etc.) are usually mixed with coco coir, light-weight expanded clay, growstone, or perlite at a certain ratio to obtain optimum treatment performance. Moreover, plants in clay show more significant growth advantages and health statuses than in zeolite or soil. Operating parameters are also significant influences on the treatment performance. This review provides theoretical and technical support for designing sustainable, environmentally friendly, and cost-effective VGSs in treating rainwater and sewage.

The cooling effect of vertical greening systems using solar radiation measurement

The cooling effect of vertical greening systems using solar radiation measurement

Green urban transition: interdisciplinary insights on green façades design in hot climates as one of crucial strategies for low-carbon development

AbstractThe purpose of this study is to present interdisciplinary insights on vertical green systems (VGS) design in hot climate zones. The approach to the VGS design proposed in this article combines architectural design, structural systems, green building and township development with sustainable urban farming, circularity, waste and water management. On the basis of in-depth study on green façade performance in hot climates, the authors identified methods derived from various fields of science which, when correctly combined, enable effective protection of plants against excessive solar radiation. The main finding of the research is the identification of the most effective combination of methods supporting healthy growth of the VGS. This set of solutions includes orientation of the façade to cardinal directions correlated with appropriate plants selection, shading strategies, such as passive and kinetic shields and organic fertilizers supporting plants’ resilience. The authors presented key challenges and opportunities of VGS application and discussed their role in the decarbonization process of the building sector. The multidisciplinary analysis of the state of knowledge highlighted areas that require further investigation, such as the practical implementation of proposed strategies and their effectiveness in real-world scenarios. Graphical abstract

A simplified modeling method for studying the thermal performance of buildings with vertical greening systems

Vertical greening systems (VGS) are considered an effective strategy to enhance the insulation performance of the building envelope. Existing methods predicting the performance of this strategy usually require a combination of mathematical modeling and building performance simulation, hence difficult for practical use. To simplify this work, this study has proposed a prediction method requiring building simulation only, by considering VGS as a shading component in the simulation work. To compare its performance, a model using conventional methods has also been proposed. A further simplification by neglecting the impact of transpiration has been investigated as well. To justify the implementation of the new method, it has been used to optimize the design of VGS for buildings located in the hot summer and cold winter areas in China. The validation result confirmed the accuracies of both methods, with the simpler method giving an insignificant lower accuracy than the conventional method, which can be compensated by its simpler prediction procedure. The implementation justification showed that for buildings in the HSCW area, VGS is suggested to be installed on the west facade, with a leaf area index of 4. This can help to reduce the heat transfer of the wall by 56.6%.

A Systematic Review of the Vertical Green System for Balancing Ecology and Urbanity

Skyrise greenery, including green roofs and vertical gardens, has emerged as an indispensable tool for sustainable urban planning with multiple ecological and economic benefits. A bibliometric analysis was used to provide a systematic review of the functions associated with skyrise greenery in urban landscapes. Key research tools, including the “Bibliometrix” R package and “CiteSpace” 6.2 R4, highlight the depth and breadth of the literature covering skyrise greenery. In 2000–2022, a total of 1474 original journal articles were retrieved. Over this period, there was an exponential increase in the number of publications, reflecting both enhanced knowledge and increasing concerns regarding climate change, the urban heat island, and urbanization. Of the total, ~58% of the articles originated from China, followed by the USA, Italy, Australia, and Canada. The research themes, such as urban heat islands, carbon sequestration, hydrology, and air quality, have been identified as the frontier in this fields. Furthermore, researchers from developed countries contributed the most publications to this domain, while developing countries, such as China, play an increasing role in the design and performance evaluation of vertical greenery. Key benefits identified in vertical green systems (e.g., green roofs and walls) include thermal regulation, sustainable water management, air-quality improvement, noise reduction, and biodiversity enhancement. In addition, several potential future research prospectives are highlighted. This review provides a comprehensive insight into exploring the pivotal role of skyrise greenery in shaping sustainable, resilient urban futures, coupled with sustainable urban planning.

Evaluating the economic sustainability of commercial complex greening based on cost-benefit analysis: A case study of Singapore’s Shaw center

Commercial complex greening is the alternative to leading the greening development of public buildings, reducing the negative impact of buildings on the environment, and achieving sustainable development goals. However, the economic sustainability of commercial complex greening remains underinvestigated. This study investigated traditional building greening economic evaluation indicators and quantitative methods according to the characteristics of commercial complexes in to provide ideas on the economic evaluation of it to fill in the blanks of CBA analysis applied to the economics of greening systems of commercial buildings. Applying cost-benefit analysis, this study evaluated the economic sustainability of vertical greening systems (VGS) and green roof systems (GRS) installed on a commercial complex in Singapore using Net Present Value (NPV), Payback Period (PBP), and sensitivity analysis to quantify and integrate personal and social life cycle costs and benefits. The methodology was based on an extensive literature review in multiple fields and rational assumptions for unavailable data. The key findings were: 1) Commercial complex greening is a feasible investment. 2) VGS has a higher economic return value, whereas GRS can achieve faster payback. 3) Well-designed greening and vitality-boosting ideas bring more economic returns than tax incentives. 4) Property value improvement, maintenance cost, and fire risk reduction were sensitive factors affecting NPV, among which property value played a decisive role, especially for VGS. 5) Extensive construction and tax policies can reduce costs and improve the economy. 6) Personal benefits generated by greening are greater than social benefits. This critical case study of a commercial complex greening project provides greening developers and operators a better understanding of the economic competitiveness of commercial complex greening implementation to promote the market application and a rationale for governments to revise existing or formulate new measures to encourage the development of green industries. Although the conclusion of this study only focuses on the economic sustainability of greening in commercial complexes in Singapore due to sample size limitations, achieving a more significant localized evaluation is potential by collecting and replacing data corresponding to regions based on this research framework. Meanwhile, quantifying more economic indicators, comparing the economy of different greening modes in commercial complexes and arranging an international database about the economic sustainability of commercial complex greening are worth further exploration in the future.

Investigating the Effect of Living Walls on Cooling Energy Consumption in Various Urban Microclimates, Building Heights, and Greenery Coverage Areas

With the aim of addressing the significant contribution of buildings to global energy consumption and the growing need to establish a more harmonious connection between humans and nature in urban environments, the concept of green vertical systems has garnered considerable attention. These systems possess the potential to enhance the energy efficiency and environmental sustainability of buildings. This study seeks to explore the impact of living walls on the energy performance of buildings, specifically investigating the influence of a living-walled urban block on the ambient air temperature and its subsequent effect on building energy consumption. By comparing the cooling energy consumption of two typical buildings situated in Shiraz, southern Iran, with varying levels of greenery in different microclimates, we further ascertain the effectiveness of living walls in reducing energy consumption. To conduct this analysis, we employed coupled simulations utilizing EnergyPlus and Envi-met, which incorporated both the outdoor microclimate and the cooling energy consumption of the buildings. The urban block under consideration consisted of 48 three-story buildings (Case A) and five-story buildings (Case B) within a site measuring 120 m × 150 m. Our findings substantiate that the implementation of a living wall system can lower the ambient air temperature by a significant extent, with an average decrease of 1.35 °C and a maximum decrease of 2.25 °C. Consequently, living walls can effectively mitigate the urban heat island phenomenon by decreasing the temperatures of the surrounding buildings. Additionally, our investigations revealed a maximum energy saving of 15%, with microclimate exerting a 4.3% influence on these savings.

A methodological approach for vertical greening systems modeling optimization: A case study in Athens, Greece

A methodological approach for vertical greening systems modeling optimization: A case study in Athens, Greece

Characteristics of Green Roof and Vertical Greening Systems and Its Application Prospect in Hong Kong

Under the background of urban population growth and increasingly prominent urban environmental problems. Green infrastructure in line with sustainable development is considered a possible solution. This paper aims to study the application of green roofs (GR) and vertical greening systems (VGS) in densely developed cities, such as Tokyo and Singapore, and provide a reference for Hong Kong. This study believes that GR and VGS have great potential in alleviating urban environmental problems in Hong Kong and can effectively provide more green development space. At the same time, it plays an active role in alleviating the urban heat island effect, reducing air pollution and energy consumption. Currently, there are some urgent problems with the application of GR and VGS in Hong Kong, such as construction cost recovery, hidden dangers of public safety, and technical construction difficulties. In addition, this paper suggests that Hong Kong should provide more investment and support for GR and VGS in legislation and technology to promote their promotion and popularization.

Concrete for Living Walls: Current Status and a New Design Recommendation

Concrete may be a promising material for application in living walls, broadening existing vertical greening systems and, most importantly, reducing installation costs. This study presents the concept of layered living concrete (LLC) wall panels that were developed and field-tested over the past 3 years. Simultaneously with long-term field observations, several laboratory studies on the selection of a rational concrete mix composition were carried out. Based on field data, the results of laboratory tests, and numerical simulations, a new LLC wall panel design was proposed. The new panel design retains the previous idea of a layered structure suitable for natural colonization by plants, but also adds improved material characteristics, rational dimensions, the economical use of water, and, potentially, the ability to hasten the greening of vertical surfaces.

Vertical greening systems serve as effective means to promote pollinators: Experimental comparison of vertical and horizontal plantings

To counteract the ongoing decline of pollinators, we need innovative and effective promotion strategies. Urban areas often function as pollinator refugia, but lack of open spaces can limit promotion measures. This scarcity in open surfaces requires rethinking the conventional flower bed. Can green walls, planted with pollinator-friendly plants, provide an alternative and attractive food source for wild and managed pollinators?We compared pollinator-friendly vertical greening systems covering approximately 6 m2 with identically planted, adjacent horizontal beds consisting of wild perennials and cultivated plant varieties at two different test sites in Baden-Württemberg, Germany. With a total of 92 planting observations and more than 2,800 single plant genera observations, we documented 12,963 pollinators and their individual plant preferences over a two-year period.While our results show no differences in the total attractiveness across all pollinators between vertical systems and horizontal plantings, honey bees had a highly significant preference for the horizontal plantings, while wild bees preferred the vertical systems. Pollinator visits increased with the height of the vertical systems, indicating that pollinators will find such vertical sources and that there are advantages to higher plantings above foot traffic. These results suggest that vertical systems are highly attractive spaces for flower visitors, especially for bumble bees and other wild bees, when planted with appropriate blooming plants and thus an innovative means to promote pollinators where horizontal open spaces are limited.

Assessment of different types of bricks in varying wall configurations in an indoor thermal environment for a semi-arid region

This study evaluates the indoor thermal benefits of seven bricks, and their combination with cavity walls, Vertical Greening Systems (VGS), and Expanded Polystyrene (EPS) insulation in a semi-arid Indian climate using EnergyPlus simulations. For walls with VGS and exterior EPS with higher heat capacity, peak summer Operative temperatures (Top) reduced up to 2.3°C, followed by cavity walls and EPS on middle of the wall (up to 1.3°C) compared to their respective bare walls. Interior EPS raised Top by up to 0.7°C. VGS and EPS minimized heat flux fluctuations due to their lower Decrement Factor. VGS exhibited superior indoor thermal comfort, with more occupants satisfied for longer durations compared to exterior EPS. This study suggests that applying VGS or EPS on the exterior (regardless of brick type) is more effective in enhancing indoor thermal comfort during hot days in semi-arid regions .

Vertical greening: The state of the art in digital modeling and simulation

The scientific literature on vertical gardens presents gaps in the systematization of botanical parameters related to modeling and simulation. To address these gaps, the article aimed to investigate and identify parameters and modeling processes necessary for configuring vertical greening systems in computer simulation software. The systematic literature review method was employed to gather all scientific publications from the past ten years. As a result, the article presents the processes for 3D modeling, the most common software, and information tables containing botanical parameters used for configuring vegetation. Additionally, the work provides an overview of studies conducted on this topic in Architecture in recent years, highlighting other gaps and shortcomings in knowledge for possible future research.

Applying vertical greening systems to reduce traffic noise in outdoor environments: Overview of key design parameters and research methods

Vertical greening can be used to absorb and scatter sound, which may reduce noise levels in street canyons. In this paper, a literature review is presented, which combines results and methods from over 40 individual studies. The article describes the guiding principles behind the acoustic effects of vertical greening and provides an overview of the prevalent research methods. The article shows that vertical greenery is effective for the reduction of mid and high frequency noise, unless air cavities or resonators are introduced inside, or behind, the systems. The review also reflects on studies with an emphasis on the application of vertical greenery in streets and urban blocks. The aim of the article is to set out the key design parameters for noise reduction that can be achieved by vertical greening, focusing on designers and engineers.

Vertical Greening Systems: A Perspective on Existing Technologies and New Design Recommendation

Vertical greening systems (VGSs) represent an emerging technology within the field of building-integrated horticulture that have been used to help counteract the global issues of urbanisation and climate change. Research and development within the field of building-integrated horticulture, despite being in the infancy stage, is steadily progressing, highlighting a broad range of achievable social, environmental, and economic benefits this sustainable development technology could provide. However, as VGS technology is relatively new, an array of different designs and technologies have been categorized collectively as VGSs, each having various performances towards the proposed and desired benefits. The purpose of this paper is to review existing VGS technologies and analyse the impact of implementation on sustainable development, and subsequently to propose a new VGS design that theoretically achieves the best possible outcomes when aiming to obtain the maximum benefits of installing a VGS. The resultant design creates new opportunities for VGS environmental amenities and maintenance, increases the scope of applications, and improves the environmental performance of the host building. The proposed design has the potential to transform VGSs beyond conventional functions of aesthetic greening to create novel ecosystems, which enhances the formation of habitats for a more diverse range of flora and fauna.

In the Search for Sustainable Vertical Green Systems: An Innovative Low-Cost Indirect Green Façade Structure Using Portuguese Native Ivies and Cork

Green façades in the urban environment represent points of biodiversity value, contributing to species conservation, acting as urban wildlife corridors connecting elements, and also aiming at sustainability, when the materials and structure are thoughtfully chosen. Ivies (Hedera spp.) are perennial climbing evergreen plants that are easy to cultivate and demand little input, and their use in vertical green systems is much appreciated but may lead to damage to the constructions in the long term. Among the 14 species of Hedera currently recognized, a few have been bred into cultivars and are available in the market for cultivation, often as exotic species. Four Hedera spp. are native to Portugal, but most cultivated species in this territory are exotic and the suitability of native species for their use in green façades has not been documented. Thus, in the present work, we describe the installation of a low-cost indirect green façade structure supported on cork panels using plants belonging to the native H. iberica and H. hibernica. The structure is installed at the Ajuda Botanical Garden, under Mediterranean conditions, on a brick and cement wall, and will enable researchers and landscape architects to follow the development of this structure as a long-term experiment, prompting the use of native species toward increased biological and technical sustainability. The preliminary results indicate that the cork structure is able to provide adequate support for the plants and that these were able to climb and develop in this structure, avoiding direct contact with the wall and the possible subsequent damage. Therefore, the structure provides a viable solution to implementing sustainable green façades with native species, on brick-cement walls, able to be replicated in other urban locations under similar environmental conditions.

Potential Use of Chilean Native Species in Vertical Greening Systems

Vertical greening systems (VGSs), i.e., living walls (LWs) and green façades (GFs), are considered a promising technology to diminish the negative effects of urbanisation. Plant selection for these systems is challenging due to the narrow spectrum of species available, and the required adaptation to specific climate conditions. Considering Chile’s rich plant biodiversity, this study aims to analyse the potential of Chilean native species to be introduced in VGSs. A total of 109 potentially usable species from the north (n = 25), centre (n = 32), south (n = 31) and the Andes Mountains (n = 21) were selected for VGSs, showing a high level of endemism (43.1%). According to the filters applied, 39 and 70 species were selected for GFs and LWs, respectively. To evaluate appreciation of Chilean native plants and their potential use in VGSs, an online questionnaire was responded by 428 individuals. Most participants agreed or strongly agreed with the use of LWs and/or GFs inside their house/apartment (75.5%) and in their garden/balcony (90.0%). Most of the participants agreed or strongly agreed with the use of Chilean native plants inside their house/apartment (75.0%) and in their garden/balcony (84.4%). Further empirical studies are still required to confirm the use of Chilean native species in LWs and GFs.