Operational Life-Cycle Assessment and Life-Cycle Cost Analysis for Water Use in Multioccupant Buildings

Life-cycle assessment (LCA) and life-cycle cost analysis (LCC) techniques are used to study a 25-year operational life cycle for plumbing fixtures and water-consuming appliances for four different multioccupant building scenarios: an apartment, a college dormitory, a motel, and an office building. Both analysis methodologies suggest that the specification of higher-efficiency fixtures and appliances is environmentally and economically justified for the scenarios considered. Additionally, both the LCA and LCC results suggest that natural gas should be used insted of electricity for water heating when both energy sources are practical options. The study found the dominant environmental impacts of domestic water consumption to be attributable to water intake, global warming potential, and fossil-fuel depletion. The dominant life-cycle cost component is for maintenance, repair, and replacement. The results of this study can be especially beneficial to long-term building owners, such as universities, because operational costs savings can be realized.     

Life-Cycle Costs of Commercial Roof Systems

The roofing industry in the United States generates annual revenues in excess of $23 billion. This represents a significant annual investment in infrastructure maintenance cost and the opportunity cost of these resources can significantly detract from an owner’s ability to invest in other areas. In addition, a failed or failing roof system represents a heightened opportunity for failure in the building envelope and inherently increases the risk of additional costs. Present roof asset management practice typically bases replacement decisions on fixed intervals, inspection results, maintenance issues, and, occasionally, failure risk. This paper develops a model for evaluating occupant costs and considering their impact in the roof management decision process through a total life-cycle cost (LCC) model that includes user/occupant cost model and correlates minimum total cost with improved intervention points in the asset deterioration cycle. The model is estimated from and applied to the extensive roof systems at Carnegie Mellon University in Pittsburgh, Pa. For these roofs, we find that the least cost roof service lives are roughly 30 years, but there can be considerable variation around this average for individual roofs.     

Knowledge-Enabled Decision Support System for Routing Urban Utilities

This paper presents a Web-based system for supporting the selection of the most suitable routes for buried urban utilities. The aim of the proposed system is to support (not make) decisions through a collaborative semiautomated environment, in which stakeholders can share information and/or study the impacts of different routing alternatives with respect to decision constraints. First, the knowledge relating to route selection for urban utilities is represented through an ontology. The ontology defines the types and attributes of infrastructure products and the surrounding areas. It also defines the impacts of routing options on surrounding areas through a set of decision criteria adopted to evaluate the effectiveness of any route in terms of its potential impacts. A set of constraints are also defined to help represent/study the decision criteria. Second, a GIS-based system has been created to help visualize route data, interact with users, and support the needed discussions among stakeholders. The portal also achieves data interoperability through wrapping existing geospatial data with ontology structures. Finally, a set of reasoners have been created to help quantify/augment some of the constraints. The system is capable of (1)?extracting the attributes of each routing option, (2)?testing the interaction/conflicts between route attributes and the constraints of the surrounding area, (3)?studying the impacts of a route as stipulated in the ontology, (4)?referring users to existing best practices to help enhance routes or address conflicts and, when needed, (5)?develop objective measures for comparing different routes. On the microlevel (street level), route options are evaluated through a “constraint-satisfaction” approach. On the macrolevel (city level), route options are evaluated through a fuzzy inference scoring system. The proposed system focuses on facility life cycle, sustainability, and community impacts. Construction costing, scheduling, labor, and equipment along with other management issues can either be added to the system or, better, analyzed through integrating the system with four-dimensional (4D) modeling tools.     

Computer-Integrated System for Estimating the Costs of Building Projects

The cost estimate is considered one of the most important and critical phases of a construction project. Preparing reliable and accurate estimates to help decision makers is the most challenging assignment that cost engineers and estimators face. For decades, practitioners in the construction industry focused only on estimating the initial cost of a facility, neglecting costs associated with operating and maintaining it. Today, more interest lies in investigating the economics of facility management, which include the cost of owning and operating a building over its useful life. This paper presents a methodology that can be used for an integrated conceptual cost estimating and life-cycle cost analysis for construction projects during their initial phase. The methodology describes the development and implementation of a system that automates the preparation of parametric cost estimates and forecasts future running costs of building projects. The system integrates relational databases, a parametric cost estimate module, an AutoCAD module, a global module, a cost estimate forecasting and decision support system module, and a life cycle costing and sensitivity analysis module. The system will automatically generate a new parametric estimate upon any modification in building design. Once the capital costs are identified, the system forecasts the cost of running and maintaining the new building throughout its expected service life. After assigning the range of deviation, a sensitivity analysis is conducted, which identifies the most sensitive parameters for further consideration and analysis. Designing the system in a user-friendly environment allows owners and decision makers to envision the feasibility of new building projects within their anticipated life cycles. Moreover, it assists architects and cost engineers in generating parametric cost estimates in a dynamic environment. A numerical case example is presented to illustrate the usefulness and capabilities of the developed system.     

Economic Viability of Water Pumping Systems Supplied by Wind Energy Conversion and Diesel Generator Systems in North Central Anatolia, Turkey

In this study, a comparison of the economic viability of wind turbine and diesel water pumping systems (WPSs) is presented for five different sites located in the north central Anatolia region of Turkey. A water pumping system was considered for water usage. The wind energy potential was investigated by using the time-series wind data taken from the Turkish State Meteorological Service (TSMS). Data were processed using FORTRAN computer code. The wind power and the amount of water to be pumped was evaluated using various wind energy conversion systems (WECSs), and unit energy and water cost were measured using life the cycle cost (LCC) method for these WECSs. Moreover, the cost of water to be delivered utilizing WPS with diesel generator (DG) was compared with the cost of water delivered viaWPS with WECS. Sinop had reasonable wind potential to produce electrical energy using WECS and the minimum cost of energy output and cost of water to be delivered were $0.24/kWh and $3.70/m3 in this observation station, respectively. In addition, if the water demand is lower than 1,000??m3 in Sinop, such as the water consumption of a household and farm, the WPS with WECS (for Turbines?1, 2, and 4) will be more plausible than the WPS with DG system. If a medium-scale WECS were set up in Sinop, it could supply both the annual electrical demand and water consumption of a household and farm. Finally, Sinop is going to be a marginal area for cost-effective electrical energy generation as the costs of WECSs are lowered.     

Slack Bus Modeling and Cost Analysis of Distributed Generator Installations

The installation and operation of distributed generators (DGs) has great potential for local utilities to improve distribution system reliability and lower their operating and expansion planning costs. To evaluate this potential, distribution system analyses must reflect its new operating environment with significant DG. Resulting tools can be utilized by both utilities and DG owners to improve their decision making algorithms. As such, this work investigates two different slack bus models for unbalanced distribution power flow and their impacts on subsequent cost analysis. The models include the traditional single slack bus model which assigns the substation as the slack bus and a distributed slack bus model which assigns slack to the substation and DGs according to network-based participation factors. Detailed expressions for cost analysis which directly depend on the distributed slack bus model are presented and discussed. Simulations illustrate that the different slack bus models have significant impacts on cost analysis. The difference in estimated annual profit for local utilities reached up to 265% using the different slack models.     

敞开式净循环水系统经济浓缩倍数的研究

运用生命周期成本法分析了首钢京唐钢铁公司某敞开式净循环水系统的生命周期成本。对该系统在运行过程中涉及的各项成本进行量化分析,并且随季节变化而改变系统边界条件,从而得出不同的浓缩倍数的优化结果。企业可由此借鉴开式循环水系统的优化设计、运行及改造。     

Risk-benefit analysis for industrial and social needs

This study develops a decision method for evaluating the social acceptability of industrial controls on hazardous materials. Decisions are based on a "multiple criteria approach" that jointly considers measures such as risk-benefit tradeoff, minimum reducible health risk, maximum acceptable cost and implicit value of human life. Health risks are calculated by combining separate estimates of production and usage patterns, emissions to air and water, effectiveness of controls, pollutant dispersion and human susceptibility. Economic benefits consider employment, trade and consumer impacts, as well as direct costs of controls. The analysis focuses on asbestos as an example hazard. Relative values of hazard reduction alternatives are examined for asbestos manufacturing exhaust filters and for asbestos substitutes in brake linings. Preliminary calculations indicate risk reductions of these alternatives cannot justify their social costs.     

热能设备的寿命周期费用及优化设计

从经济学的观点出发,分析了热能设备寿命周期内发生的各种费用,提出了以最低寿命周期费用或最大寿命周期经济效益为目标,对热能设备进行优化设计与管理的方法。     

Selecting Cost-Effective Green Building Products: BEES Approach

The Building for Environmental and Economic Sustainability (BEES) tool implements a rational, systematic technique for selecting cost-effective green building products. The technique is based on consensus standards and designed to be practical, flexible, and transparent. The Windows-based decision support software, aimed at designers, builders, and product manufacturers, includes actual environmental and economic performance data for 24 building products across a range of functional applications. BEES measures the environmental performance of building products using the environmental life-cycle assessment approach specified in the latest versions of ISO 14000 draft standards. The approach is based on the belief that all stages in the life of a product generate environmental impacts and must be analyzed. The stages include raw material acquisition, manufacture, transportation, installation, use, and waste management. Economic performance is measured using the ASTM standard life-cycle cost method. The technique includes the costs over a given study period of initial investment, replacement, operation, maintenance and repair, and disposal. Environmental and economic performance are combined into an overall performance measure using the ASTM standard for multiattribute decision analysis.     

Building Maintainability—Review of State of the Art

This paper reviews the issue related to maintainability of building and discusses works of researchers worldwide. The paper offers two approaches that could be integrated with the concepts of maintainability to augment building performance throughout its economic life. The two approaches are: (1) total quality approach via performance audit and (2) life cycle cost (LCC) approach. Various systems constructed to enhance quality delivery and maintainability of buildings were also discussed. An attempt to integrate building performance and LCC in Singapore to improve the maintainability of buildings was presented.     

Cost of managing anemia with and without prophylactic epoetin alfa therapy in breast cancer patients receiving combination chemotherapy

The cost of managing anemia with prophylactic epoetin alfa therapy versus blood transfusions in breast cancer patients receiving combination chemotherapy was studied. A retrospective study of anemia in breast cancer patients treated with four cycles of cyclophosphamide and doxorubicin with fluorouracil (CAF) or without fluorouracil (CA) was conducted. For each cycle of chemotherapy, patients were assessed for fatigue, subsequent blood transfusions administered, and potential response to and adverse effects of blood transfusions. Transfusions were given at the prescriber's discretion rather than in accordance with standard guidelines. The lowest hemoglobin concentration and hematocrit of each patient per cycle were reported. Data on these patients, along with data from published studies of prophylactic use of epoetin alfa, were used in a decision analysis of the costs associated with using epoetin alfa versus red blood cell transfusions to manage anemia. The charts of 50 patients were reviewed. In the study group, the percentage of patients with anemia and the frequency of fatigue rose with each chemotherapy cycle. In general, blood transfusions were not used. The cost of using epoetin alfa prophylactically for all four cycles was estimated at $6483 per patient for the literature-based group versus $169 for the study group. The cost of managing anemia in breast cancer patients was substantially lower when blood transfusions were used than when epoetin alfa was given prophylactically throughout four cycles of therapy with CAF or CA; the absence of standard guidelines for transfusion might have exaggerated the difference in costs.     

Incorporating Maintainability in Constructability Review Process

Life cycle cost or total cost analysis of a facility begins with the initial design concept and ends with the decommissioning of the facility. Decisions made during the design and construction phases routinely consider only the construction costs when analyzing the constructability of the project. Often the impacts of such decisions on the maintenance requirements for the facility are not fully appreciated and are therefore not formally addressed. The concept of “maintainability” addresses this concern and is a logical extension of the constructability concept. As such, maintainability may be incorporated as a part of the formal constructability review process (CRP). This article describes a model format for incorporating the best practices for maintainability into the CRP. The added life cycle value of incorporating maintainability into the CRP can only be assessed by analysis of accurate and complete maintenance cost data. Insights from such an analysis may facilitate more accurate estimates of the total costs of facilities.     

安装时间和机器受限的订单接受与并行机调度

订单接受与不相关并行机调度是订单接受与订单调度的联合决策, 广泛存在于面向定制的多品种混合生产环境中. 针对这一问题, 考虑了顺序与机器依赖的安装时间以及可加工机器限制, 并以最小化总成本为优化目标. 其中, 总成本由被接受订单的总拖期成本和被拒绝订单的总拒绝成本构成. 通过分析订单拒绝对目标的影响, 提出了列表拒绝方法和订单拒绝规则, 进而设计了协同进化遗传算法. 算法将染色体编码分解为订单列表和订单指派两个个体, 提出了基于列表拒绝方法的解码方案来进行订单拒绝决策. 由于两个个体相互独立, 且二者的进化约束不同, 因而引入协同进化策略, 并根据个体的编码特征, 分别采用单亲遗传算子和传统遗传算子进行遗传操作. 数据实验验证了算法的有效性和求解效率, 并对问题规模和订单拒绝成本对算法性能的影响进行了分析.      

Building Reuse Assessment for Sustainable Urban Reconstruction

Building reuse is a linchpin to managing solid waste. Despite the various benefits beyond contributing to sustainability that can be realized through building reuse, including direct and indirect cost savings, truncated construction schedules, and reduced site disruptions, little formal consideration has been given to this topic, which places professional engineers at a disadvantage when considering this as a design option. As each building project has its own specific requirements, reuse is not always the most economical solution, but, in cases where reuse is in part motivated by other factors such as heritage protection, substantial economic and environmental savings can be realized in tandem. Based on nearly two decades of professional experience, a generalized assessment method for reuse is proposed to facilitate benefit maximization. Applying this 10-step method, the costs related to building replacement and sustainable reuse are compared using two case histories and a theoretical building. A clear correlation is shown with the potential for savings as a function of project size.     

Construction Congestion Cost (CO3) Traffic Impact and Construction Cost

The Construction Congestion Cost System (CO3) is an integrated set of tools to estimate impact of traffic maintenance contract provisions on congestion, road user cost, and construction cost. Engineers use CO3 to produce realistic budgets and select practical contracting methods that provide an acceptable balance between construction cost and congestion. This paper demonstrates computation of impacts associated with alternative methods of maintaining traffic during construction. The Routes Sheet computes equivalent average vehicle routes for complex diversion routes. The Input Sheet provides for documentation of vehicle and route inputs and computes user cost for individual trips through the work zone, diversions, and cancellations. The Traffic Sheet computes daily traffic impacts and user costs for each construction method. The Construction Sheet computes impact of different construction methods on construction costs. The Impact Sheet summarizes daily impacts and computes total project traffic impacts, road user costs, and construction costs for all alternatives. These tools provide practical information with which engineers select construction methods whose impacts are acceptable.     

Optimization of Hollow-Fiber Design and Low-Pressure Membrane System Operation

An approach is presented for the numerical optimization of low-pressure membrane filtration processes. A multidimensional optimization of an ultrafiltration system is formulated for cost minimization and numerically solved for key optimal design and operating variables. Hollow-fiber ultrafiltration operation under steady-state conditions is assumed and optimized with respect to fiber radius, fiber length, crossflow velocity, transmembrane pressure, and system recovery. Optimizations are performed over variable raw water conditions using a sequential quadratic programming (SQP) algorithm. For typical small to moderately sized low-pressure membrane facilities (≈1 mgd), optimal fiber design and membrane system operation is predicted to be largely influenced by the characteristic dominance of capital costs over operating costs. Thus, total treatment costs tend to be optimal at values of decision variables where permeate fluxes are maximized, within the constraints prescribed by the system, and assuming a fixed membrane cost per unit area. For raw waters demonstrating apparent to significant membrane fouling, optimal membrane treatment is predicted to be achieved by using relatively narrow hollow fibers and relatively high crossflow velocities. For relatively clean raw waters demonstrating very high sustainable permeate fluxes, operating at low crossflow velocities—or perhaps even under the dead-end mode of operation—appears to provide the most cost-effective operation.     

Framework for Managing Life-Cycle Cost of Smart Infrastructure Systems

Smart infrastructure systems life-cycle costing has not receive much attention from researchers, albeit its considerable potential and proven success. This paper presents a framework to manage the life-cycle cost of these systems. The framework includes a core model for evaluating the life-cycle cost of civil infrastructure systems equipped with smart materials (fiber-reinforced concrete, sensor-embedded materials, etc.) or intelligent devices (smart valves, smart signals, etc.). The model identifies the basic cost elements that should be considered when evaluating life-cycle costs. In addition, the model identifies design and managerial factors that influence the values of these costs.     

Evaluation of Solid Waste Management System Using Fuzzy Composition

Evaluating the best alternative for a solid waste management system often requires decision makers to consider conflicting, vague, and uncertain information. Fuzzy set theory offers a possible means of managing these kinds of data or information. In this study, we propose a systematic approach to evaluating a solid waste management system in a fuzzy environment. The approach employs three main concepts: linguistic variables, fuzzy numbers, and an analytic hierarchy process. The linguistic variables are used to represent the degree of appropriateness of decision criteria, which are vague or uncertain. These linguistic variables are then translated into fuzzy numbers to reflect their uncertainties and aggregated into the final fuzzy decision value using a hierarchical structure. Through a case study, the approach is applied to the evaluation of a solid waste management system consisting of four different treatment alternatives. The results demonstrate that the developed approach can be a useful tool for evaluating a solid waste management system, where criteria are vague or imprecise.