Green Facades

The building envelope plays a crucial role in saving or consuming energy, depending on the type of the envelope
and design. Architects and engineers need to consider many issues when working with envelope designs, including
environmental issues, aesthetic appearance, occupant comfort, and view; these aspects make the envelope a
multifunctional component, thus the integration approach is the optimal method to address envelope design. In the
last decade we have witnessed the inclusion of the kinetic envelope in many typologies of buildings. Many scholars
believe the kinetic envelope improves the environmental performance of the building. The purpose of this paper is
to review the current practice and development of the kinetic envelope and to investigate its role in the improvement
of energy performance in buildings.

This research paper focuses on the period of time where cities need to function crucially to increase its flourishing green spaces. It is a progressive comprehension that the growing cities with synchronic barriers need a strong touch of green growth and creation of new public spaces which are essential to intensify the vitality of global urban environment. Moreover, the paper goes beyond the point of mentioning vertical green alone, and highlights the fabrics of an urban environment.

Current systems for greening the buildings envelope are not just surfaces covered with vegetation. Greening systems, as green roofs and green walls, are frequently used as an aesthetical feature in buildings. However, the current technology involved in these systems can maximize the functional benefits of plants to buildings performance and make part of a sustainable strategy of urban rehabilitation and buildings retrofitting. During the last decades several researches were conducted proving that green walls can contribute to enhance and restore the urban environment and improve buildings performance. The aim of this paper is to review all types of green wall systems in order to identify and systematize their main characteristics and technologies involved. So, it is important to understand the main differences between systems in terms of composition and construction methods. Most recent developments in green walls are mainly focused in systems design in order to achieve more efficient technical solutions and a better performance in all building phases. Yet, green wall systems must evolve to become more sustainable solutions. In fact, continuing to evaluate the contribution of recent green wall systems to improve buildings performance and comparing the environmental impact of these systems with other construction solutions can lead to an increase of their application in buildings and therefore result in a reduction on these systems cost. The decision of which green wall system is more appropriate to a certain project must depend not only on the construction and climatic restrictions but also on the environmental impact of its components and associated costs during its entire lifecycle.

Urban development can have a profound impact on the health and well-being of people, sustainability of cities, increasing energy consumption because of increasing urban heat island (UHI), and CO2 which is one of the environmental and social concerns. The vertical garden, as a second skin on the façade has been analyzed in this paper, is compared using several constructive alternatives in a natural and sustainable way. The main proposal of this study is a second skin (green façade) in an office building in Barcelona, Spain, that is in southwest orientation, which aims to reduce energy consumption as much as possible and improve the urban landscape and pedestrian comfort. Vertical gardens as a second skin are implemented on the building's exterior walls to intercept a quantity of solar radiation towards the vertical building envelope. The methodology is based on the evaluation of various green facade options through simulation of the different sizes of the cavity’s depth with a specific orientation. According to the result of the simulation obtained from Autodesk Green Building Studio, the cavity's depth, and the density of plants (R-Value) are very effective in the performance of the green facade which must be calculated as specified by the building main facade's material and structure, building orientation, the height of the building, and climate. This paper presents a case study that applies this approach to an office building located in Passeig de Gràcia, L’Eixample area in Barcelona.

Urban development can have a profound impact on the health and well-being of people, sustainability of cities, increasing energy consumption because of increasing urban heat island (UHI), and CO2 which is one of the environmental and social concerns. The vertical garden, as a second skin on the façade has been analyzed in this paper, is compared using several constructive alternatives in a natural and sustainable way. The main proposal of this study is a second skin (green façade) in an office building in Barcelona, Spain, that is in southwest orientation, which aims to reduce energy consumption as much as possible and improve the urban landscape and pedestrian comfort. Vertical gardens as a second skin are implemented on the building's exterior walls to intercept a quantity of solar radiation towards the vertical building envelope. The methodology is based on the evaluation of various green facade options through simulation of the different sizes of the cavity’s depth with a specific orientation. According to the result of the simulation obtained from Autodesk Green Building Studio, the cavity's depth, and the density of plants (R-Value) are very effective in the performance of the green facade which must be calculated as specified by the building main facade's material and structure, building orientation, the height of the building, and climate. This paper presents a case study that applies this approach to an office building located in Passeig de Gràcia, L’Eixample area in Barcelona.

By increasing in population and urbanization, a huge substantial pressure is imposed on resources and the environment. Urban developers, architects and engineers search for areas to plant vegetation. In dense cities, green facades and roofs can be a solution to create urban green. Besides a modern concept, it increases the ratio of greenery in urban built-up area and reveals urban green spaces. To reduce the energy consumption, the concept of nearly zero energy building (NZEBs) is important and application of sustainable forms of energy are some of the major steps taken in this direction.Different guidelines drive EU countries to use greening systems-green roofs and green façades-as a sustainable strategy to maximize environmental buildings performance. That topic is implemented in consistency to an Italian standard (UNI 11235:2015). The UNI 11235 contains the instructions for designing, building up, monitoring and maintaining the green roofs. The paper was focused to know the types of green façade systems and their mechanisms, to understand the advantages and disadvantages of green façade, and to conclude with recommendations which improve the building performance.

This paper addresses the effect of building orientation efficiency of the green facade in energy consumption, for which the case study is an urban block in Passeig de Gracia, L’Eixample, Barcelona. Nowadays, many countries are faced with the trouble of the deficiency of energy resources and the incapability of saving them. Most of this energy is consumed in the cooling, heating, and artificial ventilation of buildings. For this reason, the development of an integrated strategy like a green facade is essential to transform buildings into structures that consume less energy and to improve the occupants’ comfort conditions. From the perspective of the urban landscape, the green facade can influence the quality of life in cities due to its positive effects such as the purification of air, the absorption of carbon dioxide, and the mitigation of dust, as well as the aesthetic and psychological aspects. Such criteria are based on the adoption of suitable orientation for the green facade, w...

This paper addresses the effect of building orientation efficiency of the green facade in energy consumption, for which the case study is an urban block in Passeig de Gracia, L’Eixample, Barcelona. Nowadays, many countries are faced with the trouble of the deficiency of energy resources and the incapability of saving them. Most of this energy is consumed in the cooling, heating, and artificial ventilation of buildings. For this reason, the development of an integrated strategy like a green facade is essential to transform buildings into structures that consume less energy and to improve the occupants’ comfort conditions. From the perspective of the urban landscape, the green facade can influence the quality of life in cities due to its positive effects such as the purification of air, the absorption of carbon dioxide, and the mitigation of dust, as well as the aesthetic and psychological aspects. Such criteria are based on the adoption of suitable orientation for the green facade, w...

Together with the rapid industrialization of the world, urbanization is also uncontrollably increasing. Such an increase in urbanization exerts the greatest pressure on natural resources, obligating people to live in intense structural spaces and increasing the need for green spaces in cities. Because of the expensive costs of horizontal surfaces being "green", urban places are faced with serious green-infrastructure problems. In recent years, alternatives have been searched for to eliminate such deficiencies. These alternatives, such as rain gardens, green walls (GWs), ecological designs, and green roofs, are commonly included in urban landscape designs. Besides rocky or steep-slope natural green walls (NGWs), natural green covers over buildings, walls, and so forth, structural members are also encountered in urban or rural places. On the other hand, artificial green walls (AGWs) have recently been used as a significant component of urban design. Although the AGWs are able to address various functional needs, they have not yet gained the desired popularity because of construction costs, static loads, constructional damages, and maintenance costs. In addition, such sites are largely left to exotic species with limited ecological requirements; these species are far from meeting ecological functions and resistance to extreme conditions. This study was conducted for a benchmarking assessment of artificial and natural green walls (A&NGWs) with a high potential in urban landscape design not only for esthetics, but also for ecological and economical purposes. Plant species, initial establishment, maintenance costs, and some other parameters of selected GWs were assessed. The study was considered as pioneering research for low-cost minimum-maintenance AGWs to be included in urban landscape designs. It was concluded, on the basis of the present findings, that the GW systems established with natural plant species, rock, and other materials already existing in natural landscapes could be constructed at fairly low costs, and such wall systems could have great ecological contributions.

Green façades are becoming an important architectural element in an urban environment. Regarding the technology of the installation of green façades, one can distinguish between direct and indirect green façades, living walls and double skin façades with foliage. In addition to aesthetics of green façades, an impact on the outdoor and the indoor comfort has been proven. That is due to changed temperature and air flow conditions at the building envelope boundary. It has been proven that green façades impact lower surface temperatures of a building envelope and enhance thermal insulation properties of a building envelope, thus reduce energy demand of a building. Based on results from green façade thermal response research and growing interest in local ventilation systems one can conclude that there is potential for a free cooling of a building. Therefore, this paper presents the design and the preliminary experimental research of a local ventilation system coupled with an indirect green façade. Based on the experimental work it has been ascertained that the indirect green façade can impact a 5 K lower inlet air temperature for the local ventilation system compared to the one at the traditional façade.

Urban development can have a profound impact on the health and well-being of people, sustainability of cities, increasing energy consumption because of increasing urban heat island (UHI), and CO2 which is one of the environmental and social concerns. The vertical garden, as a second skin on the façade has been analyzed in this paper, is compared using several constructive alternatives in a natural and sustainable way. The main proposal of this study is a second skin (green façade) in an office building in Barcelona, Spain, that is in southwest orientation, which aims to reduce energy consumption as much as possible and improve the urban landscape and pedestrian comfort. Vertical gardens as a second skin are implemented on the building's exterior walls to intercept a quantity of solar radiation towards the vertical building envelope. The methodology is based on the evaluation of various green facade options through simulation of the different sizes of the cavity’s depth with a specific orientation. According to the result of the simulation obtained from Autodesk Green Building Studio, the cavity's depth, and the density of plants (R-Value) are very effective in the performance of the green facade which must be calculated as specified by the building main facade's material and structure, building orientation, the height of the building, and climate. This paper presents a case study that applies this approach to an office building located in Passeig de Gràcia, L’Eixample area in Barcelona.

This paper addresses the effect of building orientation efficiency of the green facade in energy consumption, for which the case study is an urban block in Passeig de Gracia, L’Eixample, Barcelona. Nowadays, many countries are faced with the trouble of the deficiency of energy resources and the incapability of saving them. Most of this energy is consumed in the cooling, heating, and artificial ventilation of buildings. For this reason, the development of an integrated strategy like a green facade is essential to transform buildings into structures that consume less energy and to improve the occupants’ comfort conditions. From the perspective of the urban landscape, the green facade can influence the quality of life in cities due to its positive effects such as the purification of air, the absorption of carbon dioxide, and the mitigation of dust, as well as the aesthetic and psychological aspects. Such criteria are based on the adoption of suitable orientation for the green facade, w...

This paper addresses the effect of building orientation efficiency of the green facade in energy consumption, for which the case study is an urban block in Passeig de Gracia, L'Eixample, Barcelona. Nowadays, many countries are faced with the trouble of the deficiency of energy resources and the incapability of saving them. Most of this energy is consumed in the cooling, heating, and artificial ventilation of buildings. For this reason, the development of an integrated strategy like a green facade is essential to transform buildings into structures that consume less energy and to improve the occupants' comfort conditions. From the perspective of the urban landscape, the green facade can influence the quality of life in cities due to its positive effects such as the purification of air, the absorption of carbon dioxide, and the mitigation of dust, as well as the aesthetic and psychological aspects. Such criteria are based on the adoption of suitable orientation for the green facade, which is the second layer of the facade in an office building with a curtain wall as the main facade. Since the most important factor in the implementation of a green facade is the building's orientation, the optimum orientation could be the key factor in regards to the reduction of energy consumption and cost and the improvement of overall energy efficiency. We used software that helped simulate the total energy consumption, the cost, and the energy use intensity annually and monthly. Consequently, after testing was carried out, it was proven that a green facade as a second layer with a southeast and/or a southwest orientation results in the maximum energy saving in a coastal city with a Mediterranean climate like Barcelona.

This paper addresses the effect of building orientation efficiency of the green facade in energy consumption, for which the case study is an urban block in Passeig de Gracia, L’Eixample, Barcelona. Nowadays, many countries are faced with the trouble of the deficiency of energy resources and the incapability of saving them. Most of this energy is consumed in the cooling, heating, and artificial ventilation of buildings. For this reason, the development of an integrated strategy like a green facade is essential to transform buildings into structures that consume less energy and to improve the occupants’ comfort conditions. From the perspective of the urban landscape, the green facade can influence the quality of life in cities due to its positive effects such as the purification of air, the absorption of carbon dioxide, and the mitigation of dust, as well as the aesthetic and psychological aspects. Such criteria are based on the adoption of suitable orientation for the green facade, w...

A mathematical model of an exterior wall covered with climbing vegetation has been developed to evaluate the thermal effects of plants on heat transfer through building facades.  This model allows for analysis of how various plant physiological parameters such as leaf area index, average leaf dimension, and leaf absorptivity can improve facade thermal performance by reducing the exterior wall surface temperatures and heat flux through the façade.  The model has been verified with a set of experiments that measured both bare and vegetated facade thermal performance of an educational building in Chicago, IL, during the summer.  A sensitivity analysis was also conducted to elucidate the relative impacts of plant characteristics, weather conditions, climate zones, wall assembly types, and facade orientation on vegetated facade thermal performance.  Overall, results herein show that a plant layer added to the facade can improve its effective thermal resistance by 0.0-0.7 m²K/W, depending on a range of inputs for wall parameters, climate zones, and plant characteristics (particularly leaf area index).  These improvements are especially pronounced in predominantly warm climates with high solar radiation and, to a lesser extent, low wind speeds. The model developed herein can ultimately be used both to access facade thermal improvements in existing buildings retrofitted with green walls and to design green walls for optimal energy efficiency in new construction.

High-density urban development areas have several problems associated with them, such as the formation of urban heat islands, traffic noise, and air pollution. To minimize these problems, the green façades (GFs), which are used to guide climbing plants to grow vertically on building facade, are focused on by researchers and architects. This study focuses on GF application strategies and their optimizations for thermal comfort in a transitional space in a hot-humid climate. First, field measurements were collected from GF projects located in Guangzhou, China, in summer 2017. Second, a simulation method using computational fluid dynamics (CFD) was used to investigate the thermal effects of the GF's foliage. Finally, seven GF typologies and one unshaded comparison model were used for simulations in three scenarios with south, east, and west orientations and compared to evaluate the effects of GFs on the thermal environment of the transitional space. The results of field measurements reveal that the GF reduced average Physiologically Equivalent Temperature (PET) by 2.54 °C, and that of CFD simulations reveal that three typologies of GFs are more effective in regulating the thermal environment in the summer. The results of this research provide support for further studies on the thermal effectiveness and design options of GFs for human comfort.

The paper shares the results of a design submitted to a competition launched by the University of Wageningen, focusing on the retrofitting action of one of the existing towers of the former Bijlmerbajes prison complex in Amsterdam. The effort of an interdisciplinary team was oriented to demonstrating that it is possible to imagine the architectonic environment as a living organism, being part of the new food production chain, sponsoring zero kilometer products and increasing buildings’ sustainable comfort while reducing their energy consumptions. Promoting a healthy lifestyle, an awareness of how to environmentally friendly behave and keeping the ecological footprint as low as possible were the main goals we wanted to achieve with our retrofitting and regenerative proposal of the GreenTower.

Urban development can have a profound impact on the health and well-being of people, sustainability of cities, increasing energy consumption because of increasing urban heat island (UHI), and CO2 which is one of the environmental and social concerns. The vertical garden, as a second skin on the façade has been analyzed in this paper, is compared using several constructive alternatives in a natural and sustainable way. The main proposal of this study is a second skin (green façade) in an office building in Barcelona, Spain, that is in southwest orientation, which aims to reduce energy consumption as much as possible and improve the urban landscape and pedestrian comfort. Vertical gardens as a second skin are implemented on the building's exterior walls to intercept a quantity of solar radiation towards the vertical building envelope. The methodology is based on the evaluation of various green facade options through simulation of the different sizes of the cavity’s depth with a specific orientation. According to the result of the simulation obtained from Autodesk Green Building Studio, the cavity's depth, and the density of plants (R-Value) are very effective in the performance of the green facade which must be calculated as specified by the building main facade's material and structure, building orientation, the height of the building, and climate. This paper presents a case study that applies this approach to an office building located in Passeig de Gràcia, L’Eixample area in Barcelona.

Vertical gardens have become important strategies for urban heat island migration in recent years. However, the simulation tools for green façade (GF) with climbing plants coupling the shading and wind-induced effects are still lacked. This study focused on GF effects on human thermal comfort (HTC) optimization in a transitional space. The main purpose was to develop a couple method on HTC simulations. Field measurements in a hot-humid climate area were conducted to obtain the parameters of GF foliage layers. A couple simulation method with Ansys Fluent, Ladybug, and Honeybee tools was developed. Seven GFs layouts on a standard balcony model were simulated. In field measurements, the Ave. global irradiation was reduced by 73.29%, leaf area index was measured at 1.56-3.61, and foliage cover ratio was measured at 49.74-92.88%. In the simulations, the results of the Ave. wind velocity were reduced by 0.20-0.77 m s −1 , the Ave. air temperature was reduced by 0.2°C, the Ave. mean radiant temperature was reduced by 0.5-7°C, and the Ave. physiological equivalent temperature was reduced by 0.3-3.2°C. The couple method could support the architectural and landscape design integrating with the GFs in future.

This article presents a comprehensive literature review of Vertical Greenery System (VGS) in tropical areas, its benefits, its carbon sequestration potential and its calculation methodologies, and its potential for urban heat island (UHI) and climate change mitigation. The contemporary VGS has evolved from the seventh-century beginnings of the Hanging Gardens of Babylon to the vertical urban farms of today in Singapore and Japan. The VGS has demonstrated a significant role in mitigating urban climate change impacts by the potential use of carbon sequestration from vegetation. However, studies on carbon sequestration rate and the methodologies used for calculation are still rather vague. Therefore, this paper reviews existing methodologies for evaluating carbon sequestration rates in tropical climate plants and makes suggestions of potential plants for optimum carbon sequestering.