The development of life-cycle costing for buildings

The history of the application of life-cycle costing (LCC) began in the UK in the late 1950s and, until now, the state of its development as a concept is not clear. A literature review is presented that shows the changing approaches to LCC by drawing on four major academic journals and 45 peer-reviewed papers. The review verifies that there is a revival of interest in using LCC in tandem with other life-cycle methodologies for research on sustainable building. It also presents a set of methods that are applicable to model and estimate the life-cycle costs of ‘conventional’ and ‘green’ buildings with the objective of distinguishing them. Through the information gathered, it provides a centralized source of reference for the assumptions used in LCC calculations concerning some key input parameters. The finding shows an increasing trend of publications on the evaluation of economic options for green building designs and performance. The directions are clear that the concepts and methods have to evolve to a state where they will help to integrate and optimize economic, social and environmental considerations to deliver more sustainable built environments in the future.     

A model for earthquake risk management based on the life-cycle performance of structures

Over 50 years of design life, buildings are exposed to different magnitudes and frequencies of earthquakes that require consideration of life-cycle cost (LCC). The LCC entails quantifying the building performance under seismic hazard and investments throughout the life of the structures. Traditional LCC utilises probabilities of being in different damage states. However, for buildings with inherent irregularities (e.g. vertical irregularity and plan irregularity), these probabilities are not readily available. In this paper, a system-based approach, utilising fuzzy set theory, is used to quantify the possibility of being in different damage states. The analysis is limited to study the effect of seismic exposure on the building LCC. The proposed method is illustrated with two case studies, a six-storey reinforced concrete (RC) building located in Vancouver, Canada, and vulnerability of an urban centre with 1000 RC buildings. Furthermore, sensitivity analysis is carried out to highlight the impact of different building performance modifiers on the LCC.     

Goal directed life cycle costing as a method to evaluate the economic feasibility of office buildings with conventional and TI‐façades

Transparent insulation systems (TI‐systems) of less than 20cm thick have been developed as an alternative to opaque wall insulation and windows, which provide a financial return to building occupants when applied to building façades. Lack of detailed cost analysis of TI‐systems is a major constraint to the application of TI‐wall and TI‐glazing in buildings. A goal directed life cycle costing (LCC) technique and sensitivity analysis used to evaluate the economic feasibility of TI‐applications in office buildings form the basis of this research. It was undertaken as part of research to determine optimum energy and cost performance of TI‐systems for external cladding of high‐rise and low‐rise office buildings in temperate and tropical climates. The LCC of the buildings with conventional façades were compared with those with TI‐façades. The results show that LCC can be used to evaluate the economic feasibility of low carbon technologies such as TI‐systems effectively. A detailed account is provided of how different sources of cost data can be captured, collected and integrated to perform selective goal directed LCC analysis in the absence of detailed historical LCC data. The use of the goal directed LCC method and cost influence diagram presented in this research can be adopted as a standard method for assessing the economic feasibility of applying low carbon technologies to buildings.     

我国城市住宅全生命期能源消耗分析

为了全面掌握我国城市住宅建筑的全生命期能源消耗情况,文章运用全生命期评价模型对我国2007年所建城市住宅的能耗总量加以计算,同时借助敏感度分析方法对总能耗的敏感因素进行识别。研究结果表明,运行能耗在全生命期能耗中所占比例为70%;在能源消费结构方面,煤炭和电力占据了总能耗的80%;全生命期能耗量对于建筑采暖能耗密度和其他生活终端能耗密度较为敏感。该研究加深了对我国城市住宅全生命期能源消耗的了解,将推动全生命期评价模型在我国建筑领域的应用。     

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 cost analysis and life-cycle assessment of the second-generation benchmark building subject to typhoon wind loads in Hong Kong

Tall buildings located in Hong Kong can suffer great damage caused by typhoon hazards throughout their lifetimes. In addition, the effect of wind hazards may be exacerbated due to increases in the typhoon intensity and frequency caused by the climate change effect. Therefore, developing a framework to evaluate and quantify the damage caused by wind hazards on tall buildings from the economic perspective is critical for engineers and building owners in designing a cost-effective tall building. In this study, an economic damage indicator, life-cycle cost, is measured by using a probabilistic method called life-cycle cost analysis (LCCA). Moreover, the building sector is one of the biggest contributors to greenhouse gas (GHG) emissions, and the environmental impact that may be generated in intervention activities after wind-induced damage occurs is analyzed. An environmental impact indicator, embodied carbon emission, is quantified by employing another probabilistic method called life-cycle assessment (LCA). Therefore, an integrated methodology combining the LCCA and LCA is proposed to evaluate potential damage costs and environmental impact caused by typhoon hazards on tall buildings.     

A multi-objective feedback approach for evaluating sequential conceptual building design decisions

Conceptual design decision-making plays a critical role in determining life-cycle environmental impact and cost performance of buildings. Stakeholders often make these decisions without a quantitative understanding of how a particular decision will impact future choices or a project's ultimate performance. The proposed sequential decision support methodology provides stakeholders with quantitative information on the relative influence conceptual design stage decisions have on a project's life-cycle environmental impact and life-cycle cost. A case study is presented showing how the proposed methodology may be used by designers considering these performance criteria. Sensitivity analysis is performed on thousands of computationally generated building alternatives. Results are presented in the form of probabilistic distributions showing the degree to which each decision helps in achieving a given performance criterion. The method provides environmental impact and cost feedback throughout the sequential building design process, thereby guiding designers in creating low-carbon, low-cost buildings at the conceptual design phase.     

Life-cycle assessment of post-disaster temporary housing

The estimation of energy consumption and related CO₂ emissions from buildings is increasingly important in life-cycle assessment (LCA) studies that have been applied in the design of more energy-efficient building construction systems and materials. This study undertakes a life-cycle energy analysis (LCEA) and life-cycle CO₂ emissions analysis (LCCO₂A) of two common types of post-disaster temporary houses constructed in Turkey. The proposed model includes building construction, operation and demolition phases to estimate total energy use and CO₂ emissions over 15- and 25-year lifespans for container houses (CH) and prefabricated houses (PH) respectively. Energy efficiency and emission parameters are defined per?m² and on a per capita basis. It is found that the operation phase is dominant in both PH and CH and contributes 86–88% of the primary energy requirements and 95–96% of CO₂ emissions. The embodied energy (EE) of the constructions accounts for 12–14% of the overall life-cycle energy consumption. The results show that life-cycle energy and emissions intensity in CH are higher than those for PH. However, this pattern is reversed when energy requirements are expressed on a per capita basis.     

Inventory analysis of LCA on steel- and concrete-construction office buildings

A life-cycle inventory model for the office buildings is developed in this paper. The environmental effects of two different building structures, steel and concrete, are intercompared. The results show that the steel-framed building is superior to the concrete-framed building on the following two indexes, the life-cycle energy consumption and environmental emissions of building materials. It is found that the life-cycle energy consumption of building materials per area in the steel-framed building is 24.9% as that in the concrete-framed building, whereas, on use phase, the energy consumption and emissions of steel-framed building are both larger than those of concrete-framed building. As a result, lower energy consumption and environmental emissions are achieved by the concrete-framed building compared with the steel-framed building on the whole life cycle of building. The present study also provides a good method of assessing the performance of energy saving and environmental protection of different building structures based on a whole life cycle.     

住宅建筑的全寿命周期能耗研究

以全寿命周期理论为基础,将其运用到建筑领域,从而把住宅建筑全寿命周期边界划定为6个阶段并对其各阶段进行能耗研究,列出了各阶段能耗的简单计算公式。运用DeST-h软件对建筑运行阶段的能耗进行了模拟计算,并以此进行了实例的运用分析,最后提出了住宅建筑在全寿命阶段的节能措施。通过对住宅建筑全寿命周期能耗分析,有助于人们对建筑运行能耗以外的其他隐性能耗加以重视,从而更全面的促进建筑的节能减排。     

浅谈节能建筑与工程造价

结合我国建筑能耗的特点,简单介绍了节能建筑与建筑节能的涵义及区别,针对节能建筑造价管理进行了探讨,阐述了全寿命周期造价管理的概念、工作理念及内容,并提出了节能建筑周期造价管理的发展建议,以指导实践。     

Energetische Sanierung von Schulgebäuden in den neuen Bundesländern – Sanierungsprojekt Förderschule Rathenow

Energy efficiency improvements for school buildings in Germany's new federal states; Rathenow special school refurbishment project. Current energy saving measures for existing buildings focus on refurbishment of schools and other educational buildings. The building described in this article represents the standard type of a large‐panel construction series in the new federal states. Due to the large number of buildings (540) constructed in this way the project can act as a model for similar projects. Initial studies indicated that structural refurbishment measures for these buildings are required as a matter or urgency. The energy performance calculations for the building showed good agreement between the calculated demand values and actual heating energy consumption values and can serve as basis for predictions of energy savings through various refurbishment measures. The new DIN 18599 calculation standard enables significantly more differentiated consideration of boundary conditions such as occupied periods, occupancy levels, internal heat sources, and the effect of night setback. Based on comparative calculations, different refurbishment concepts can be developed and assessed.     

Energy performance and indoor environmental quality in Hellenic schools

School buildings constitute a major part of the non-residential building stock, though due to their operational characteristics, they represent a low percentage of the overall energy balance of the building sector. Although health and productivity of pupils and teachers is strongly affected by the indoor environmental quality of their school, poor indoor air quality has been reported in published literature, even so for recently constructed school buildings. The same applies for the energy consumption, with large amounts of energy being wasted because no energy saving measures are applied for the operation of schools. This paper presents the outcome of a study on the energy performance of Hellenic school buildings. The general features of the contemporary building stock are presented along with the results from an energy survey in 135 Hellenic schools. The derived energy consumption benchmarks are compared with published literature. Finally, the energy performance and indoor environmental quality of a representative sample of schools in metropolitan Athens are assessed in a holistic approach to the “energy efficiency – thermal comfort – indoor air quality” dilemma. The IEQ assessment was based on an objective evaluation by monitoring crucial indoor conditions and a subjective occupant evaluation using standardized questionnaires. The potential of several energy conservation measures is evaluated in terms of energy savings and reduction of greenhouse gas emissions along with the related payback periods.     

Learning from failure: understanding the anticipated–achieved building energy performance gap

Over the past 20 years a number of studies have identified and provided explanations for a significant ‘performance gap' between designed and actual energy performance of buildings. The anticipated and achieved energy performance of an advanced, innovative building that aspired to net-positive energy performance is studied: the Centre for Interactive Research on Sustainability (CIRS) building at the University of British Columbia in Vancouver, Canada. Selected performance ‘failures’ that became evident during operation of CIRS are studied for how they were discovered and the efforts required for their resolution: the energy systems and associated controls and monitoring. The key findings show the barriers were neither economic nor technical. Instead, the primary impediments were institutional regimes – arising from the ways that various life-cycle stages were specified, contracted and implemented. The key issues emphasize the importance of having meaningful and effective building energy monitoring capabilities, an understanding of energy system boundaries in design and analysis, crossing the gaps between different stages of a building life cycle, and feedback processes throughout design and operation. The disclosure of ‘failure’ and lessons learned is a valuable contribution to subsequent advancement for the building stakeholders and the wider professional and research communities.     

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.     

既有公共建筑节能改造的全寿命周期费用研究

以既有公共建筑为研究对象,采用全寿命周期费用分析的方法,分析出所发生的四大费用:改造费用,使用费用,拆除费用和政府的补贴,以及详细的费用构成,建立了节能改造的LCC估算模型。详细介绍了既有公共建筑节能改造全寿命周期费用中节约费用的计算方法,并且引入碳排放权交易理论,运用碳交易价格确定出公共建筑节能改造后,每年可以节约的费用,不仅可以更好地衡量出节能改造的经济效果和减排效果,而且为我国进入国际碳交易市场打下基础。     

Repurposing a historic school building as a teacher’s village: exploring the connection between school closures,housing affordability,and community goals in a gentrifying neighborhood

ABSTRACT

The redevelopment of urban school buildings of historical value has the potential to contribute to the needs of current residents. Using a case study from Chicago, IL—where more than 50 schools in primarily minority and low- and moderate-income neighborhoods were closed in 2013—this article shows how a community group “Community As A Campus” (CAAC) sought to repurpose a former school site for community purposes in an already mixed-used, amenity-rich, and walkable area. CAAC advocated for housing for educators in the gentrifying neighborhood of West Town. The project, however, created tensions within residents from density related to market-rate units. This paper argues that the future of historic buildings to be preserved sustainably would depend on the ability of local leaders to find a balance between economic and community goals.     

保温材料在围护结构中的全寿命周期经济评价

运用全寿命周期经济评价理论,建立围护结构全寿命周期经济评价模型,并通过实际工程分析和计算建筑围护结构采用节能材料后的全寿命周期成本,从而得出结论:建筑围护结构运用节能材料不仅降低建筑能耗,同时也降低了建筑全寿命周期成本。     

基于绿色建筑标准的历史文保区建筑节能环保技术集成应用

概述了绿色建筑的概念及基本要求,并介绍我国绿色建筑评价的标准。以新建居家养老服务中心及社区卫生服务站建设工程为例,研究历史文化保护区建筑节能环保技术集成应用。提出生态优先,以人为本,因地制宜及经济、社会、环境效益相统一的设计原则,从节地、节能、节水、节材、室内环境质量和运营管理方面在历史文化保护区建筑集成应用各项绿色环保技术,以降低建筑能耗,减少污染物排放,实现可持续发展的目标。