Environmental performance optimization of window-wall ratio for different window type in hot summer and cold winter zone in China based on life cycle assessment

This study aims at analyzing the environmental impact of each process of a typical office building over its entire life cycle in Shanghai, China, and finding out a suited limited value for window-wall ratio (WWR) of different orientation and window materials by comparing the results of different scenarios. Life cycle assessment (LCA) is used as a tool for the assessment of energy consumption and associated impacts generated from utilization of energy in building construction and operation.When looking at the impacts due to building external envelope production, we observed a small but significant environmental benefit as WWR increasing. Depending on the window materials, the impact is reduced by 9-15%. The environmental benefit associated with the changing in building external envelope production mainly results from the high coefficient of recovery of window materials, include window-frame and glass. But for building use phase, WWR with different window types or orientation has various effects on environmental burden. The environmental impact of office buildings is dominated by the operation stage, although the environmental burden of material production for low-E hollow glass window is larger than single glazing window, the environmental performance of building with low-E hollow glass window is better than other window materials.     

Life cycle,sustainability and the transcendent quality of building materials

This paper explores the relationship between the life cycle of engineering works and their sustainable and transcendent qualities, and considers the possibility of creating durable works with ephemeral materials. This paper also studies the impact of urban growth and its infrastructures on the environment through the consumption of raw materials and energy. City metabolism is one of the main causes of environmental deterioration, and present-day tendencies make it foreseeable that both urban and infrastructure development shall continue to increase. Although the expression “sustainable construction” is being used more and more, it is necessary to distinguish between the sustainability of the construction activity and the sustainability of works constructed. Both the materials and technologies used since ancient times have allowed many past works to have lasted thousands of years. Some were made out of permanent materials such as stone while others were made out of more ephemeral materials such as adobe bricks or cob walls. Structures built with Roman cement are still standing after 20 centuries. The overall durability of built structures depends on the durability of their materials. Transcendent construction was made possible either using permanent materials or more ephemeral materials, providing the project had taken the need for maintenance into consideration. The development of building works in a modular fashion makes the repairing action of modifying materials or parts of works possible without destroying its basic structure. With our present-day knowledge, plain concrete permits to create transcendent structures that could last several centuries.     

Towards a successful voluntary building environmental assessment scheme

Voluntary building assessment schemes have emerged worldwide to help assess the environmental performance of buildings. As building environmental assessment is a rapidly evolving field, the scope and details of such assessment schemes are continuously undergoing updating and refinement. Substantial efforts have been devoted to the design and improvement of the assessment schemes to make them capable of defining an objective building profile. Although most of the existing schemes are voluntary, many fail to encourage participation of the building investors and designers. In order to widen acceptance, the design of the scheme should be oriented towards the manner in which investors make decisions. This paper provides an overview of the vital elements and changes needed, so as to make a voluntary building environmental assessment scheme more attractive and successful, and will include reforms not only in the scope and the credit weighting philosophy but also in its nature.     

Design,construction, and thermal performance evaluation of an innovative bio-based ventilated fa(c)ade

The energy consumption of the construction sector and its overall environmental impact has greater potential for improvement than those of many other sectors. Most energy consumed throughout the lifecycle of a building is expended during its operation and maintenance, for which the building envelope plays an important role. This study reports on the design, construction, and thermal performance evaluation of a ventilated façade. The façade should be quickly assembled, disassembled, and stored in containers for easy onward transport. Such features comply with the Rules and Building Code of the Solar Decathlon Middle East 2018 and the relevant Eurocodes. The façade is constructed using bio-based materials in keeping with the principles of a circular economy. The exterior cladding consists of sanitary paper, grass, reeds, recycled textiles, drinking water treatment waste, bio-based polyester resin, and other materials. Temperature and the air velocity measurements recorded on the façade in Dubai showed that the façade had contributed to cool temperatures within the apartment, particularly during the hottest hours of the day. The façade is a promising option for climates with hot summers and mild winters as it contributes to reducing energy consumption and the environmental impact of building materials.     

Optimization model for the selection of materials using a LEED-based green building rating system in Colombia

Buildings have a significant and continuously increasing impact on the environment because they are responsible for a large portion of carbon emissions and use a considerable number of resources and energy. The green building movement emerged to mitigate these effects and to improve the building construction process. This paradigm shift should bring significant environmental, economic, financial, and social benefits. However, to realize such benefits, efforts are required not only in the selection of appropriate technologies but also in the choice of proper materials. Selecting inappropriate materials can be expensive, but more importantly, it may preclude the achievement of the desired environmental goals. In order to help decision-makers with the selection of the right materials, this study proposes a mixed integer optimization model that incorporates design and budget constraints while maximizing the number of credits reached under the Leadership in Energy and Environmental Design (LEED) rating system. To illustrate this model, this paper presents a case study of a building in Colombia in which a modified version of LEED is proposed.     

苏州月亮湾国际中心建筑生命周期评价

众所周知,建筑物对环境的影响很大。我们可以将建筑看作一种特殊的产品来对待,引入生命周期评价方法评价建筑对环境的影响。文章主要采用日本产业技术综合研究所LCA研究中心开发的评价系统AIST-LCA Ver.2对高层建筑——苏州月亮湾国际中心建筑(每100 m2的建筑面积)进行生命周期评价。在评价过程中,建筑的生命周期分为5个过程,即建材准备阶段、建筑建造阶段、建筑运行阶段(运行年限为50年)、建筑拆除阶段和建筑垃圾处理阶段。得到的评价结果为建筑的运行阶段和建材的准备阶段对环境的影响较大,其次为建筑垃圾处理阶段和拆除阶段,建筑建造阶段对环境产生的影响最小。对环境影响较大的影响类型为城市空气污染、富营养化、全球变暖等。     

SArch for assessing environmental impact of Thai housing

This paper introduces SArch, an environmental impact assessment tool developed in Thailand. SArch can be used to assess the environmental impact of construction materials throughout the lifecycle of buildings. The assessment starts with the raw materials and follows their preparation, transportation, utilization and maintenance to post-utilization or destruction. Five categories of impact are considered: global warming, acidification, eutrophication, ecological toxicity and smog. SArch can be used to assess the environmental impact of materials in the building design phase as well as the impact of existing buildings. An example of using SArch for the assessment of a residential house in Thailand is provided.     

绿色建筑材料评价体系研究

简述了绿色建筑材料的概念和发展,论述了绿色建筑对建筑材料的要求,并根据我国国情提出了从资源消耗、能源消耗、环境影响、耐久性等方面建立一个绿色建筑材料评价体系。该绿色建筑材料评价体系包括基本标准和专项标准两部分,给出了两部分标准的内容及评分办法。该绿色建筑材料评价体系的建立可为我国政府部门制定统一的绿色建筑材料评价体系提供参考。     

A generic model of Exergy Assessment for the Environmental Impact of Building Lifecycle

A generic model of Exergy Assessment is proposed for the Environmental Impact of the Building Lifecycle, with a special focus on the natural environment. Three environmental impacts: energy consumption, resource consumption and pollutant discharge have been analyzed with reference to energy-embodied exergy, resource chemical exergy and abatement exergy, respectively. The generic model of Exergy Assessment of the Environmental Impact of the Building Lifecycle thus formulated contains two sub-models, one from the aspect of building energy utilization and the other from building materials use. Combined with theories by ecologists such as Odum, the paper evaluates a building's environmental sustainability through its exergy footprint and environmental impacts. A case study from Chongqing, China illustrates the application of this method. From the case study, it was found that energy consumption constitutes 70-80% of the total environmental impact during a 50-year building lifecycle, in which the operation phase accounts for 80% of the total environmental impact, the building material production phase 15% and 5% for the other phases.     

ETFE foil cushions in roofs and atria

Building fenestration can be responsible for a significant impact on the environment created in a building, affecting, either adversely or beneficially, both the health and perceptions of the occupants. Alternative to traditional fenestration solutions have been available for a great many years, one of which is ethylenetetrafluoroethylene (ETFE) a co-polymer of PE and tetrafluoroethylene which has been used for the past 20 years for atria and other overhead glazing. This study examines both the effects of ETFE manufacture and its use in buildings. This study has considered both its performance in terms of fitness for purpose and in comparison to glass, the common alternative. Some built examples of ETFE foil roofs are presented. It is concluded that ETFE foil is an appropriate technology for certain building applications, in particular those where the volume of space is large and high light levels are important. ETFE foils can improve the environmental performance of a building and may reduce the overall environmental burden incurred from the construction process itself and the burden of the building during its lifetime.     

A generative facade design method based on daylighting performance goals

Successful daylighting design is a complex task which requires the designer to consider numerous design elements and their effects on multiple performance criteria. Facades, in particular, include many variables which may dramatically impact daylighting performance. Genetic algorithms (GAs) are optimization methods which are suitable for searching large solution spaces, such as those presented by design problems. This article presents a GA-based tool which facilitates the exploration of facade designs generated based on illuminance and/or glare objectives. The method allows the user to input an original 3d massing model and performance goals. The overall building form remains the same while facade elements may change. Ten parameters are considered, including materials and geometry of apertures and shading devices. A simple building data model is used to automatically generate a 3d model of each solution. Results from single- and multi-objective case studies are presented to demonstrate a successful goal-driven design exploration process.     

Life cycle inventory of buildings: A calculation method

Traditionally, life cycle assessment (LCA) is mostly concerned with product design and hardly considers large systems, such as buildings, as a whole. Though, by limiting LCA to building materials or building components, boundary conditions, such as thermal comfort and indoor air quality, cannot be taken into account. The life cycle inventory (LCI) model presented in this paper forms part of a global methodology that combines advanced optimisation techniques, LCI and cost-benefit assessment to optimise low energy buildings simultaneously for energy, environmental impact and costs without neglecting the boundary conditions for thermal comfort, indoor air quality and legal requirements for energy performance. This paper first outlines the goal and scope of the LCI. Then, the partial inventory models as well as the overall building inventory model are presented. Finally, the LCI results are shown and discussed for one reference dwelling for the context of Belgium.     

Life Cycle Assessment of the inclusion of phase change materials (PCM) in experimental buildings

The present work evaluates the environmental impact of including phase change materials (PCM) in a typical Mediterranean building. A Life Cycle Assessment (LCA) is developed for three monitored cubicles built in Puigverd de Lleida (Spain). It is possible to control the inner temperature of the cubicles using a domestic heat pump for cooling and an electrical radiator for heating: The energy consumption is registered to determine the energy savings achieved. The aim is to analyze if these energy savings are large enough to balance the environmental impact originated during the manufacturing of PCM.Some hypothetical scenarios, such as different systems to control the temperature different PCM types or different weather conditions are proposed and studied using LCA process to point out the critical issues. Furthermore, a parametric analysis of the lifetime of buildings is developed.Results show that the addition of PCM in the building envelope, although decreasing the energy consumption during operation, does not reduce significantly the global impact throughout the lifetime of the building. For the hypothetical scenario considering summer conditions all year around and a lifetime of the building of 100 years, the use of PCM reduces the overall impact by more than 10%.     

A new life cycle impact assessment approach for buildings

This study examines factors resulting in an environment burden (local EB) in the region where a building is located, and suggests a method for assessing it. The environmental burden (attached EB) caused by the expansion of infrastructures, such as, roads and parking lots for supporting buildings is also considered. An integrated life cycle impact assessment approach is proposed for buildings based on social cost account, called a region-type life cycle impact assessment (R-LCIA) here, which can give not only the total environment burden on a global scale but also the environment burden in a region scale and the attached EB. Furthermore, as an example of the R-LCIA, the environmental impact of a store building is assessed, and the effects of its location, structural type, and energy system are discussed.     

A study regarding the environmental impact analysis of the building materials production process (in Turkey)

Because of the negative impact of buildings on the environment, building materials and, particularly, their production process are important factors. However, this impact differs from country to country and according to ecological applications in place at the production plants. Depending on the success rate of these applications, impact on environment during production of building materials is reduced. Turkey plays a major role in production of building materials, and consequently, the impacts of the global environmental problems are also experienced in this country. Therefore, reducing the environmental impact of any kind is a prominent issue, regionally and globally.     

Eco-Bat: A design tool for assessing environmental impacts of buildings and equipment

This paper presents the features of Eco-Bat, a computer program developed to assess the environmental impacts of buildings, including construction materials and energy consumed, during its life cycle. The methodology used to evaluate environmental impacts based on a life cycle assessment (LCA) approach, compatible with ISO 14040 standards, is detailed. The data are mainly extracted from an environmental impacts database, Ecoinvent, which contains values for the manufacturing and elimination of numerous materials as well as other processes. Two applications are presented to illustrate the possibilities offered by Eco-Bat. The first one is a comparison of different variants of building facades. The second example shows the analysis of a whole building including its energy consumption.     

LCA profiles for building components: strategies for the early design process

Construction professionals are required to integrate environmental concerns in the earliest design phases. However, environmental assessments need large amounts of precise data that are typically not available in the early design process, as most variables are still fluid. To address this concern, a new approach explores how environmental information on building components can be simplified for strategic use early in the design process in a Danish context. In this paper, life cycle assessments (LCAs) are undertaken for several hundred typical external wall solutions, based on relevant standards. A full bivariate linear regression analysis is performed, showing statistically significant correlations with strong direct relationships between environmental impact categories. A simplified LCA profile consisting of total primary energy, global warming potential and acidification potential is developed. This simplified LCA profile presents environmental data in a more understandable way, creating a strategic overview that can be easily used by non-technical clients and construction professionals in the early design stages. This has a scientific and statistical validity generated by environmental assessment standards, and creates a parallel between the precision of the approach and its time of use in the design process.     

Building houses with local materials: means to drastically reduce the environmental impact of construction

This paper describes the process of materials selection, design and construction used for a series of small residential buildings in Southern France. Whenever possible, materials were resourced in situ in order to minimise the environmental impact of the new buildings. In particular, the process of materials selection, stone masonry with stabilised in situ soil mortar, and the form of construction are outlined. Guidance for a more generalised adoption of the design process is also provided. The energy consumed in the building of one house is compared to a typical concrete house. By adopting local materials the amount of energy used in building decreased by up to 215% and the impact of transportation by 453%. However, adoption of local materials in developed countries can be hindered by the loss of traditional building crafts and a lack of appropriate building standards. These problems are also discussed in this paper.     

Visualisation of impact of time on the internal lighting of a building

With the increasing realisation of the importance of information and elicitation of knowledge, the need for improved methods of extraction and abstraction of information and knowledge has gained equal attention. To this end, visualisation methods have been viewed an effective way of abstracting information. Over the past three decades, these methods have undergone a rapid revolutionary progress, supported by sophisticated visualisation tools, analytical and simulation methodologies and techniques.During this period, the visualisation of an object, such as a building, 'in time' - viewing it from different perspectives - has gained significant attention and developments have been underpinned by sophisticated software technology. However, visualisation of a building 'through time' - viewing it as it degrades through aging - has received limited attention. Indeed, the ability to visualise the behaviour of a building, through time, has the potential to yield significant advantages: at the design phase, the informed choice of different building materials enables the architect to meet the client's technical, aesthetic and economical objectives. Extending the same capabilities to the maintenance phase can result in the development of just-in-time schedules which can prevent wastages without compromising the service to the users of the building. With advances in the BIM technology and the promised paradigm shift in the manner stakeholders collaborate and interact, the ability to simulate and visualise the time-based behaviour of building elements can assist decisions relating to both design and scheduling.In this paper, the overall model of the visual building design and maintenance is proposed and its practicality is demonstrated through its application to the building lighting system. The overall process is modelled and generalised and the lighting system is introduced as an example where the research work can be applied: the time-related behaviour of different light sources under the impact of intrinsic and environmental factors is modelled and expressed in a mathematical form which facilitates visualisation through the use of Visual User Interface.     

An assessment tool for the energy, economic and environmental evaluation of thermal insulation solutions

The paper discusses an assessment tool, used for the energy, economic and environmental evaluation of Thermal Insulation Solutions (TIS). The results of the assessment undertaken with this tool can take the form of a simple rating system in order to enable users to perform comprehensive comparisons amongst various building materials and TIS. A ranking expressed by A, B and C classes is used for energy, environmental and economic parameters. By evaluating the materials, the tool supports the users to make decisions, depending on preferences or priorities such as the energy efficiency achieved, the total cost and the environmental performance. The assessment tool is applied for the double cavity wall and the External Thermal Insulation Composite Systems (ETICS) as they are used throughout Europe, both in new constructions and in the renovation of existing buildings.