Net-zero buildings: incorporating embodied impacts

The design and assessment of net-zero buildings commonly focus exclusively on the operational phase, ignoring the embodied environmental impacts over the building life cycle. An analysis is presented on the consequences of integrating embodied impacts into the assessment of the environmental advantageousness of net-zero concepts. Fundamental issues needing consideration in the design process – based on the evaluation of primary energy use and related greenhouse gas emissions – are examined by comparing three net-zero building design and assessment cases: (1) no embodied impacts included, net balance limited to the operation stage only; (2) embodied impacts included but evaluated separately from the operation stage; and (3) embodied impacts included with the operation stage in a life cycle approach. A review of recent developments in research, standardization activities and design practice and the presentation of a case study of a residential building in Norway highlight the critical importance of performance indicator definitions and system boundaries. A practical checklist is presented to guide the process of incorporating embodied impacts across the building life cycle phases in net-zero design. Its implications are considered on overall environmental impact assessment of buildings. Research and development challenges, as well as recommendations for designers and other stakeholders, are identified.     

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.     

超高层建筑结构优化过程中的环境成本计算

近年来中国大陆掀起了超高层建筑的兴建热潮。超高层建筑体量巨大,其碳排放和能源消耗对环境有显著影响。在评估和优化超高层建筑的全生命周期环境成本时,提出了一个全新的全生命周期模型。新模型有两大特征：首先,同时考虑了建筑材料的空间分布与时间特征;其次,把单尺度生命周期概念拓展到多尺度生命周期概念,以从更多角度来研究碳排放情况。建立了一个基准超高层建筑模型来阐释对新模型的应用。根据初步研究结果,应用新方法可以选择出更优化的结构设计方法,以最大程度减少碳排放量。     

筑屋于木——木质结构建筑的综合环境足迹分析

建筑业对资源、能源的巨大消耗,造成的严重环境污染等。该文用生命周期分析方法,对木质结构建筑在全生命周期内（包括建材物化阶段和建筑运行阶段）的能耗进行理论分析,从而确定选择合适的建筑材料和形式对环境的综合影响,为木结构建筑的发展提供一些思路。     

Life cycle assessment of end-of-life vehicle recycling in China: a comparative study of environmental burden and benefit

The continuous increase in car ownership in recent years has led to a sharp increase in the number of end-of-life vehicles (ELVs). In this paper, life cycle assessment (LCA) was used to establish a mathematical computation model and nested iterative inventory data in order to assess the environmental impact of recycling a passenger ELV. The model was used to calculate and analyse the environmental burden caused by dismantling, reverse logistics, and recycling and to assess the environmental benefit of recycled materials, remanufactured engines, and recovered energy. The results showed that human toxicity potential was the only factor that had a higher environmental burden than benefit, with a difference of approximately 36%. The incineration of automotive shredder residues was the main contributing factor, accounting for 79% of the total contribution. Moreover, aluminium recycling and plastic recycling contributed the most to abiotic depletion potential and photochemical ozone creation potentials, respectively.     

Environmental efficiency in residential buildings – A simplified communication approach

For all actors involved with planning, developing and managing buildings, the environmental impact relating to energy use and the quality of the indoor environment are both aspects of major concern. It is crucial that a reduction in the environmental impact of a building is not achieved through compromising the indoor environment. This paper presents a method to assess user satisfaction related to the indoor environment and the environmental impact related to the energy use of the building, i.e. the environmental efficiency of the building. This environmental efficiency comprises two indices that are calculated separately but displayed in the same diagram to facilitate communication of complex information. This approach forms part of the Swedish life cycle based environmental assessment tool for buildings, EcoEffect. The present paper presents and exemplifies the environmental efficiency of buildings using data from 26 Swedish multi-family residential buildings and proposes a number of reference values. The concept can be used as an overarching objective for environmental management of a property firm's building stock or for evaluating targets set in the planning process for a new building. It can also be used for environmental rating of buildings, which would probably increase the communication value further. The aggregated indices are rough but proportionately straightforward to calculate and easily communicated. In addition, they address the environmental impacts of buildings in a much more comprehensive way than the current practice.     

基于支付意愿法的建筑物化环境影响量化研究

以建筑的物化环境影响分析为出发点,对该过程所消耗的资源、能源及有毒物质所造成的环境影响进行定量研究。论文界定了建筑物化环境影响内涵,根据国际环境毒理和化学学会环境评价体系确定12种环境影响要素,依据BEES(Building for Environment and Economic Sustainability)软件计算出建筑全生命周期的环境影响清单,基于支付意愿理论构建了建筑物化环境影响量化模型,并确定江苏地区各环境影响要素的货币值。最后,计算出江苏省某住宅建筑单位面积上环境影响货币值。     

Integrated assessment method for building life cycle environmental and economic performance

Life cycle assessment (LCA) is a powerful tool to identify a building’s environmental impact throughout its life cycle. However, LCA does have limits in practice because it does not consider the economic aspect of project implementation. In order to promote LCA application, a more comprehensive evaluation of building life cycle environmental and economic performance must be performed. To address these issues, we propose life cycle green cost assessment (LCGCA), a method that combines LCA with life cycle costing (LCC). In LCGCA the building’s environmental loads are converted to environmental costs based on the trading price of CO₂ certified emission reductions (CERs). These environmental costs are then included into the building life cycle cost. Subsequently an evaluation index of green net present value (GNPV) for LCGCA can be obtained. A governmental office building in Beijing was studied using LCGCA. Several design options were compared and the sensitivity of the CER price was analyzed. The research also shows that conclusions reached by LCGCA may be different from those of traditional LCC, which does not include environmental costs. The application of LCGCA needs the support of environmental policies. A sound environmental tax mechanism is expected to be established in China soon, which will enable LCGCA to be a useful tool to guide sustainable building design efficiently.     

水泥生命周期中物化环境状况的研究

本文运用生命周期评价方法研究水泥生命周期中的物化环境状况 ,主要考虑水泥生产工艺过程、运输过程造成的直接环境影响和电力生产、燃煤生产造成的间接环境影响。通过对三种用新型干法技术生产的水泥的物化环境状况分析发现 ,水泥生产工艺过程和电力生产是造成水泥物化环境影响的主要原因。在水泥生产工艺过程中 ,熟料烧成造成的环境影响占主要部分 ;在水泥造成的环境影响类型中 ,全球变暖和粉尘排放是造成水泥潜在环境影响的主要因素 ;随着水泥强度的提高 ,水泥的环境影响负荷和资源耗竭系数均增大。     

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.     

基于BIM的小型节能建筑生命周期环境影响和成本分析

被动式超低能耗建筑通过被动式设计策略、高性能的围护结构和高效的设备体系降低其使用阶段能耗。零能耗建筑在此基础上,采用太阳能光伏发电等可再生能源系统,进一步降低不可再生能源消耗。这两类节能建筑的材料和设备系统的隐含能耗、环境影响和成本通常高于一般建筑,同时对构件的后期维护和替换提出了更高的要求。因此,有必要从生命周期的范畴分析其环境和经济效益。建筑信息模型（BIM）能够为建筑项目的建造、运行和拆解等阶段提供多专业共享的数据平台。本文基于BIM,通过LCA和LCC方法对一座小型住宅建筑在不同节能目标情景下的生命周期全球变暖潜势值（GWP）、一次能耗（PE）和成本（LCC）进行分析和比较。结果表明,零能耗乃至正能源建筑在降低一次能耗和GWP方面具有明显优势,被动式超低能耗建筑也具有良好的环境效益。在经济效益方面,由于住宅建筑能源价格较低,如果按近年的价格指数计算,零能耗建筑和被动式超低能耗建筑的初建成本和后期构件替换成本增量将抵消其使用阶段节约的能耗成本,因此生命周期成本高于普通节能建筑。如果未来50年能源价格涨幅超过建筑安装价格涨幅,那么零能耗建筑在生命周期成本方面将具有优势。     

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.     

建筑生命周期评价工具的现状分析

建筑业是我国的支柱产业,对环境也造成了深刻的影响。对建筑物进行生命周期评价是促进建筑业可持续发展的重要手段。到目前为止,世界范围内已经开发出了一些建筑物生命周期评价的软件工具,它们都是针对各自的国家开发出来的,不适用于所有国家。我国在建筑业生命周期评价的研究也已开始,但总的说来还很不深入。     

Life cycle analysis of housing

This paper reports the findings of a project to assess the costs and benefits of adopting environment‐friendly construction practices for social rented housing in Scotland. Two contrasted dwelling specifications — one for a conventional building (the Control) and one for an environmentally responsible building (Eco‐Type 1) — are compared using Life Cycle Analysis and Life Cycle Costing methodologies. An assessment is made of the environmental and economic implications of adopting environmentally conscious construction practices in social rented housing. It is concluded that the provision of environmentally responsible dwellings could bring large‐scale reductions in the environmental burden of housing, and economic savings for housing providers and tenants over the life cycle of a dwelling with only a small increase in capital costs.     

建筑垃圾制免烧免蒸砖的环境影响评价

随着城镇建设的快速发展,建筑垃圾剧增,对环境和社会的影响越加严重,建筑垃圾的减量化、资源化和再利用成为建筑业可持续发展亟待解决的问题。免烧免蒸砖是一种替代传统粘土实心砖的新型墙体材料,有利于节能、节地、利废,促进循环经济发展,具有良好的经济效益和社会效益。文章通过对建筑垃圾制免烧免蒸砖生产工艺的调查,系统分析了生产过程的各项环境排放因素,并运用生命周期评价理论和方法,对其生产过程的环境影响进行定量研究和综合测算。针对建筑垃圾制免烧免蒸砖的生产过程中主要环境影响因素,包括温室气体和粉尘的排放等,提出了改进建议。     

Assessing the environmental performance of buildings: trends,lessons and tensions

ABSTRACT

Since the 1970s, intense discussions have occurred within the research and practitioner communities on how to assess and influence the environmental performance of buildings. Many different methods, criteria and tools were developed to raise awareness, enable goal formulation, support design and decision-making processes, and evaluate a building’s environmental performance. This development can be retraced through the example of the works of Raymond J. Cole, who made an important contribution to this scientific debate. The integration of environmental performance into a sustainability assessment, the ongoing development of life cycle assessment (LCA) methods, and clients’, financiers’ and assessors’ different demands for environmental performance assessment, raise additional questions and highlight the conflicting goals. Six topics are examined in relation to current developments: the further development of the classic ‘three pillars’ sustainability model; the suitability of assessment criteria and indicators; the handling of technological progress; the discounting of environmental impacts; the environmental assessment of existing buildings; and the further development of legal requirements. ‘Time’ is a key factor relating to LCA, weighing current versus future emissions, ecological value and recycling potential of existing buildings or ‘options’ for different ways to use the building in future. Recommended actions are provided for key stakeholders.     

Environmental impact of dwellings in use: Maintenance of façade components

The use of dwellings contributes significantly to human-induced environmental burden in a number of ways, including energy consumption and the maintenance and replacement of building components. The present study deals with the maintenance and replacement of external doors and windows in a Dutch reference dwelling and describes how life cycle assessment (LCA) methodology can be applied to quantitatively assess the environmental impact of various maintenance scenarios for the façade components. First, the most effective way to reduce the negative environmental impact in this context is to replace existing single and double glazing with high efficiency double glazing, thereby reducing energy consumption for space heating. Second, the use of timber frames causes less environmental impact than PVC frames with a steel core. Third, extending the service life of building components decreases the input of material resources, production processes and the waste processing of building components during the service life of a dwelling, which is beneficial to the environment. Maintenance activities should only be performed when needed, keeping the building components in good condition while minimising the transportation movements of maintenance workers. Finally, protecting timber components with an alternative paint that contains less solvent does not lower the assessed environmental impact, but low-solvent paint may be preferred because of health aspects both for maintenance workers and occupants of the dwelling.     

建筑材料生命周期中环境状况的评价与研究

建筑材料是构建建筑物的物质基础,其环境影响是建筑物生命周期环境影响的一个重要组成部分。通过生命周期评价方法评价建筑材料在预建构阶段、建设阶段、后建设阶段三部分产生的环境影响。积极推行建筑材料的再生循环,贯彻资源与环境可持续发展的战略决策。     

Gebäude aus Lebenszyklusperspektive – Ökobilanzen im Bauwesen

Life cycle assessment in the construction sector. Under the impression of an increasing demand for sustainability thinking in the building and construction sector, the method of Life Cycle Assessment (LCA) is constantly gaining relevance. LCA is a method to quantify and assess the environmental impacts of technical systems – in the building and construction sector, these could be both, building products or complete buildings – over their entire life cycle. In the construction sector, LCAs of building products have been well established, while LCAs of entire buildings are just now becoming more common. The German certificate for sustainable buildings strongly promotes this development by including Life Cycle Thinking into the rating of the sustainability of buildings. Due to this development, planners and other stakeholders in the construction industry have to face the necessity of life cycle based environmental optimization of a building already during the planning phase of the building. With the cooperation of LCA experts and experts in the field of assistance in the planning and construction process, dedicated and feasible solutions for this task can be developed. This article provides an overview on LCA in the building and construction sector and presents a possible approach to the question of planning‐integrated environmental optimization of buildings.     

Life cycle analysis model for New Zealand houses

Globally designers are concentrating on minimising the impact their buildings make on the environment. Although many claim their buildings to be sustainable, unless an objective analysis is carried out, it is not possible to determine the impact that a particular building has on the environment. This paper describes a method that has been developed at the University of Auckland for a detailed life cycle analysis of an individual house in New Zealand based on the embodied and operating energy requirements and life cycle cost over the useful life of the building.