Evaporative cooling strategies in urban areas: The potential of vertical greening systems to reduce nocturnal heat stress

This research is part of a project that aims to create a simulation workflow to design adaptive facades to not only reduce the energy demand of buildings and provide a good level of indoor comfort. but also to mitigate the urban heat island effect. The anthropogenic climate change results in a steady increase of hot days. tropical nights and heavy rainfall. affecting the quality of human comfort. especially in urban areas not only in hot regions of the world but also in Central Europe. Vertical greening systems are often a first-choice mitigation strategy to improve the deteriorating situation. By combining the use of natural resources like rainwater and solar radiation. the greening evaporates water and provides natural cooling. This paper deals with the efficiency and feasibility of vertical greening systems towards a relief in heat stress by simulating different constructions under local circumstances of three climate zones. focusing on the night-time. To carry out the simulations with microclimate simulation tool ENVI-met. an urban apartment complex was designed and provided with different kinds of vertical greening to investigate the various positive effects resulting from the green façade. As a shading device. the greened walls showed a significant decrease of wall surface temperatures of up to 18K. However. restricted transpiration fluxes obstruct exploiting the full potential of evaporative cooling. especially during night-time.

Blue-green infrastructure as a new trend and an effective tool for water management in urban areas

Blue-green infrastructures (BGI) integrate solutions implemented to enhance water management and landscape values for more climateresilient and livable cities. BGI have created an opportunity to renew the natural structure of water balance in cities through the increase in rainwater retention and enlargement of permeable areas. The review of the literature on BGI development and solutions showed that the most popular BGI elements in terms of urban water quantity and quality were rain gardens, green roofs, vertical greening systems, and permeable pavements. Their structure and effectiveness were presented and reviewed. Despite the consensus between researchers that BGI benefit urban hydrology, differences in runoff decreased (2%-100%) lowering the peak flows (7%-70%) and infiltration (to 60%) or evapotranspiration (19%-84%) were reported. Due to an individual technical structure, each BGI element plays a specific role and there is no universal BGI solution against water-related problems. We inferred that the most effective ones were individually adapted solutions, which prevent from a stressor. The greater variety of solutions in a given area, the more benefits for the urban environment. Our analyses showed that a holistic and co-creative approach to create blue-green networks should be considered in modern water management plans.

VERTICAL GREENING SYSTEM FOR ENVIRONMENT RESPONSIVE ARCHITECTURE

Vertical greening systems can help mitigate the urban heat islands, increase the thermal efficiency of the buildings, save cooling energy and enhance air quality by using the vegetation's natural processes. However, since vertical greening schemes need materials and energy to be built, there are questions about whether they actually deserve to be adopted and how their environmental efficiency can be improved. The study aims to evaluate verticalgreening systems' environmental efficiency and to study essential factors for efficient and sustainable building construction.

Closing Water Cycles in the Built Environment through Nature-Based Solutions: The Contribution of Vertical Greening Systems and Green Roofs

Water in the city is typically exploited in a linear process, in which most of it is polluted, treated, and discharged; during this process, valuable nutrients are lost in the treatment process instead of being cycled back and used in urban agriculture or green space. The purpose of this paper is to advance a new paradigm to close water cycles in cities via the implementation of nature-based solutions units (NBS_u), with a particular focus on building greening elements, such as green roofs (GRs) and vertical greening systems (VGS). The hypothesis is that such “circular systems” can provide substantial ecosystem services and minimize environmental degradation. Our method is twofold: we first examine these systems from a life-cycle point of view, assessing not only the inputs of conventional and alternative materials, but the ongoing input of water that is required for irrigation. Secondly, the evapotranspiration performance of VGS in Copenhagen, Berlin, Lisbon, Rome, Istanbul, and Tel Aviv, cities with different climatic, architectural, and sociocultural contexts have been simulated using a verticalized ET0 approach, assessing rainwater runoff and greywater as irrigation resources. The water cycling performance of VGS in the mentioned cities would be sufficient at recycling 44% (Lisbon) to 100% (Berlin, Istanbul) of all accruing rainwater roof–runoff, if water shortages in dry months are bridged by greywater. Then, 27–53% of the greywater accruing in a building could be managed on its greened surface. In conclusion, we address the gaps in the current knowledge and policies identified in the different stages of analyses, such as the lack of comprehensive life cycle assessment studies that quantify the complete “water footprint” of building greening systems.

Towards sustainable landscape irrigation using novel design of water collecting systems from atmospheric humidity condensation

The paper proposes an innovative improvement to the water collectors from atmospheric humidity condensation by introducing non-hydrophobic substances to speed up the water condensation and the dropping off process using simple technology, inexpensive and with high quality materials with the finality to favor sustainable irrigation in regions characterized by water resources scarcity favoring greening generally. The innovative collector’ design and experimentation conduced confirm the possibility to collect water from air humidity in different regions with reduced rain days as semi desertic zones enhancing the gain of desertification process, harvesting water in urban landscape, in vertical greening and roof gardens. The first principal innovative aspect of the novel design collector is the fast capacity of condensation caused from the method of design of the used materials and fast capacity of releasing water collected to contrast the undesired evaporations. The second innovative aspect is the reduced volume to permit a diffused and unexpensive implants which can be distribute suitably on the targeted landscape. Reduced costs and simplicity of fabrication announce real possibility of use in underdeveloped and poor countries to increase vegetation diffusion firstly and contributing on sustainable agriculture and architecture.

Reviewed Interpretations and Inspirations on the Development and Strategies of Garden City Theory in Singapore

Reconceptualising the construction of Garden Cities in Singapore from the perspective of the history of urban development and urbanization, in conjunction with the development and trends of vertical greening systems. To summarise the principles of development in modern ecosystems in the context of rapid urbanisation and high population density trends: 1. Long-term planning and adherence to ecological principles are required for urban construction and development. 2. Urban development should insist on controlling and guiding the urbanisation process. 3. Strong executive and coordination capacity of the government is an essential force for the development of new cities. 4. The cultivation of urban culture is required to be initiated by the government to promote social consensus and directing the power of the public. 5. Respond to the trend of the times and make flexible use of science and technology (vertical ecosystems) to solve urban problems.

An Investigation into Residents' Willingness to Pay for Vertical Greening in the Renovation of Existing Residential Areas for Greenhouse Gases Reduction- A Case Study of Hangzhou City

There are numerous buildings in existing residential areas in Hangzhou City, which results in much carbon emissions and the formation of greenhouse gases that have exerted significant ad-verse impacts on the living comfort of citizens in Hangzhou City. It is imperative to conduct a greening renovation of buildings in existing residential areas in Hangzhou City. Vertical greening, as a significant measure of renovation, has received much attention. In this paper we use double-bounded discrete choice format to elicit public’s willingness to pay (WTP), and the economic benefits of vertical greening reduces greenhouse gases in Hangzhou City were preliminarily estimated, and the factors that affect residents' payment and participation. A total of 1089 valid samples were obtained via the face-to-face field interview. There were 250 (23.0%) respondents who refused to pay, whose data were subject to processing with Spike model, which had been proved to be more advantageous than traditional models in dealing with zero response problems. Families in Hangzhou City would pay 702.55 Chinese yuan (CNY) each year. The economic benefit of the project is 1.141–1.433 billion CNY. The factors affecting WTP were explored by demographic characteristics,social psychology༌knowledge of the environment and theory of planned behavior. The results showed that there were obvious statistical relationships between the age, income, family members, cognition of vertical greening and subjective norms of respondents and their WTP. Meanwhile, the feedback information was collected and analyzed, with the results showing that increasing income, setting up compensation mechanism, promoting the publicity of environmental protection, and disclosing the flow of funds would conduce to residents' participation in the renovation of vertical greening.

Environmental Sustainability of Building Retrofit through Vertical Greening Systems: A Life-Cycle Approach

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.