► We discuss new interpretations of sustainable development. ► We show the uncertainty of defying a sustainable building. ► Social requirements of sustainable building are investigated. ► The ...importance of cross-scale evaluations between a building and surroundings is demonstrated. ► Sustainable building represents a state of regenerative resilience of built environment.
A review of definitions of sustainable building shows that the terminology needs clarification as many difficulties exist in identifying sustainability in the built environment. The study starts by examining the recent evolution of the concept of sustainable development. Latest interpretations of this terminology are considered, before analysing what sustainability means in the built environment. This paper focuses on constrains which prevent a simple definition and identification of what is a sustainable building. Systems for sustainability assessments are often insufficient to recognize sustainability of buildings given the strong environmental and technological approach of these systems. In particular, the dependence of the concept of sustainability on time, scale, domain and social uncertainties is discussed. Some requirements for a better definition of a sustainable building are indicated. This paper shows that a greater attention should be given to social and economic aspects. The importance of the cross-scale relationships between a building and its surroundings, together with the ever changing flows between them, limits the possibility to define the sustainability at the level of single building, and it encourages looking at larger and crossing scales. Finally, this paper shows that a building is sustainable if it contributes to the sustainability through its metabolism and by doing this it favours a regenerative resilience of the built environment among all the domains of sustainability.
The aim of Energies’ Smart Cities and Urban Management Section is to present new research results and new proven practices aimed at optimizing the energy use of smart cities and improving the energy ...efficiency in urban management ...
•Natural materials are a valid option for sound absorption treatments.•An inverse method to predict the acoustical properties of nine natural fibers is presented.•Using a least-square fit procedure, ...the acoustic impedance and propagation constant laws are calculated.•The inverse method allows to determine different physical parameters of each fiber.•The empirically derived laws allow to include natural fibers in software for room acoustics.
Natural materials are becoming a valid option for sound absorption treatments. In particular, among them, natural fibers have received increasing attention given their good thermal insulation properties, lack of harmful effects on health, and availability in large quantities. This paper discusses an inverse method to predict the acoustical properties of nine natural fibers. Six vegetative fibers: kenaf, wood, hemp, coconut, straw, and cane; one animal fiber, sheep wool; recycled cardboard; and granular cork are investigated. The absorption coefficient and the flow resistance for samples of different thickness have been measured. Moving from the Delany-Bazley model, this study compares the impedance tube results with the theoretically predicted ones. Then, using a least-square fit procedure based on the Nelder-Mead method, the coefficients that best predict both the acoustic impedance and the propagation constant laws are calculated. The inverse approach used in this paper allows to determine different physical parameters and to obtain formulas to include the investigated natural fibers in software modelling for room acoustics applications.
•Cross-disciplinary review is performed for showing benefits of green roofs.•Green roofs have several benefits for energy, water and pollution management.•Experiments show that green roofs must ...consider specific climatic conditions.•Lifecycle analysis ensures the economic feasibility of green roofs.•Quantification of the green roof performances needs to consider technical design.
Green roofs have been proposed for sustainable buildings in many countries with different climatic conditions. A state-of-the-art review of green roofs emphasizing current implementations, technologies, and benefits is presented in this paper. Technical and construction aspects of green roofs are used to classify different systems. Environmental benefits are then discussed mainly by examining measured performances. By reviewing the benefits related to the reduction of building energy consumption, mitigation of urban heat island effect, improvement of air pollution, water management, increase of sound insulation, and ecological preservation, this paper shows how green roofs may contribute to more sustainable buildings and cities. However, an efficient integration of green roofs needs to take into account both the specific climatic conditions and the characteristics of the buildings. Economic considerations related to the life-cycle cost of green roofs are presented together with policies promoting green roofs worldwide. Findings indicate the undeniable environmental benefits of green roofs and their economic feasibility. Likewise, new policies for promoting green roofs show the necessity for incentivizing programs. Future research lines are recommended and the necessity of cross-disciplinary studies is stressed.
•The current status of UHI mitigation studies in Toronto are reviewed.•Three locations in Toronto are selected for the environmental simulation.•The effects of cool pavement, cool roof and urban ...vegetation on UHI are discussed.•UHI mitigation strategies are simulated and discussed in both summer and winter.•The results support new policies for sustainable urban development in Toronto.
Increasing awareness of the urban heat island (UHI) effect has raised attention about the outdoor thermal comfort in cities worldwide. Several studies in the last decades have revealed how critical the UHI effect can be in a cold climate, such as in Canadian cities. As a result, in Toronto, one of the cities experiencing the highest rate of building development in developed countries, UHI mitigation strategies are currently the object of extensive debates. This study evaluates different UHI mitigation strategies in different urban neighbors of Toronto, selected according to their building density. The effects of cool surfaces (on the roofs, on the street pavements or as vegetation areas) are evaluated through numerical simulations using the software ENVI-met. Having obtained the surface temperature, outdoor air temperature, mean radiant temperature, and physiologically equivalent temperature, this study compares the possible mitigation of net surface radiation and thermal radiative power. The results demonstrate that the duration of direct sun and the mean radiant temperature, which are strongly influenced by the urban form, play a significant role in urban thermal comfort. Finally, this research supports new policies for promoting sustainable urban development in Toronto, and suggests design strategies for a more resilient urban planning.
Proposing new materials and systems to improve buildings' performance and energy efficiency often requires testing their performance in the field. Experimental performance characterization of new and ...existing building systems is crucial to understanding their behaviour. Full-scale experimental test cell facilities have been at the forefront of experimental performance evaluation in building-related research, as they provide a realistic representation of buildings, including environmental conditions, assembling challenges, and operational characteristics. In this paper, trends in the design and construction of outdoor testing facilities are first discussed. Then, based on the current literature and the knowledge gained through visits to multiple facilities, the new test cell facility “BeTOP”, located in Toronto (Ontario), is described. BeTOP is a full-scale experimental facility with the capacity to perform multiple experimental tests simultaneously. This paper describes its characteristics, including structure details, testing capabilities, system details, current monitoring campaigns, and future testing potential. The paper concludes by showing that the design of a full-scale testing facility is crucial to observe the long-term performance of new systems under variable boundary conditions in a continental climate with cold winters and hot and humid summers.
In recent years, there has been a growing interest in the design of courtyards for the microclimatic enhancement of outdoor spaces. However, there is still little knowledge regarding the thermal ...performance characteristics of courtyards, particularly in hot and humid climates. This study evaluates the ability of unshaded courtyards for providing thermally comfortable outdoor spaces according to different design configurations and scenarios, including the orientations, height and albedo of wall enclosure, and use of vegetation. The software ENVI-met was used as a tool for simulating the thermal performance of courtyards in the hot and humid climate of Kuala Lumpur, Malaysia. The PMV and the number of hours per day that a courtyard could be enjoyed once the proposed design suggestions were implemented are assessed. Likewise, the Physiologically Equivalent Temperature (PET) index allowed to further explore the thermal comfort conditions of courtyards. As a result, guidelines are proposed in order to optimize the design of courtyards towards enhancing their thermal performance characteristics. In particular, the study shows that according to design parameters such as the building height ratio, an abundance in the amount vegetation the courtyard can achieve an acceptable level of thermal comfort for the tropics and may be enjoyed by its users for a long duration of daytime even during the noontime. Finally, this paper stresses that only well designed courtyards may represent a valid option for sustainable built environments.
•Outdoor thermal comfort of several unshaded courtyards are compared in a summer day in a hot and humid climate.•Both Ta and Tmrt are proven to be too high in most of the courtyards.•Maps of PMV show values above 4 for long part of the day.•Surrounding the courtyards with tall buildings is highly favorable to reduce the incoming solar radiation.•The use of trees improves the thermal comfort, whereas grass covering may increase significantly the relative humidity.
The rapid urban expansion in East-Asian cities has increased the need for comfortable public spaces. This study presents field measurements and parametric simulations to evaluate the microclimatic ...characteristics in a university campus in the tropical climate of Kuala Lumpur, Malaysia. The study attempts to identify the thermally uncomfortable areas and their physical and design characteristics while debating on the circumstances of enhancing the outdoor comfort conditions for the campus users. Simulations in Envi-met and IES-VE are used to investigate the current outdoor thermal conditions, using classic thermal metric indices. Findings show high levels of thermal discomfort in most of the studied spaces. As a result, suggestions to improve the design quality of outdoor areas optimizing their thermal comfort conditions are proposed. The study concludes that effective re-design of outdoor spaces in the tropics, through adequate attention to the significant impacts of shading and vegetation, can result in achieving outdoor spaces with high frequency of use and improved comfort level.
Display omitted
•Adequate attention to shading and vegetation results in enhancing outdoor thermal comfort.•The outdoor spaces with the highest PMV/PET values embrace similar characteristics.•The fully shaded areas can be used by users for 80% of the studied period.•The unshaded spots embrace high thermal discomfort levels for over 80% of the time.
Although it is often stated that the energy consumption in buildings accounts for more than 30% of total global final energy use, only a few studies analyze updated data about the current building ...energy consumptions or focus on comparing different countries. Similarly, models that predict future trends in building energy demand often use contrasting algorithms which result in diverse forecasts. Scope of this paper is to present and discuss data taken from several studies about the building energy consumptions in US, EU, and BRIC (Brazil, Russia, India, and China) countries and to provide an updated inventory of useful figures. Comparisons among countries are used to show historical, actual, and future energy consumption trends. Data presented by the World Bank, the United Nations Environment Program, the Intergovernmental Panel on Climate Change, and the International Energy Agency are compared with national reports as well as with research studies. The variety of the approaches used in each of the previous sources was considered fundamental to allow a complete review. The paper shows that the total building energy consumptions in BRIC countries have already overcome those in developed countries, and the continuous increase in the building stock of the BRIC countries creates an urgency for promoting building energy efficiency policies in these countries. At the same time, the policies actually adopted in developed countries are insufficient to guarantee a significant reduction in their building energy consumption in the years to come. In the current scenario, at least a doubling of the global energy demand in buildings compared to today’s levels will occur by 2050. To avoid this forecast, cost-effective best practices and technologies as well as behavioral and lifestyle changes need to be diffused and accepted globally.
PDF
