Life Cycle Cost Considerations Research Articles

Holistic energy efficient design approach to sustainable building using monitored energy management system

Building sector focuses on surpassing challenges linked to energy efficiency and mitigation measures related to greenhouse gas emissions, in consequence, it needs to improve building performance in the interest of decreasing impact over environment. Buildings with reduced long-term operating cost, environmental-friendly and moderate construction costs can be achieved only by multi-object optimization and cross-disciplinary analysis, embodying a holistic approach. Following the main principles of the holistic sustainable design approach, the paper presents a sustainable experimental modular laboratory involving various strategy in regard with sustainable building, as resource, cost and material efficiency, health and well-being, environmentally conscious design, life cycle design, modular design, reusable/recyclable element, environment-friendly demolition method, safety design, consideration of life cycle cost, materials cost and waste disposal cost. Besides the installation of renewable energy sources and conservation of energy, the holistic construction of laboratory included also an integrated design with consideration for technology, operation and maintenance, which involved the implementation of a monitored energy management system. The system provides an accurate overview of the building’s performance during operational phase. Although the monitoring is still in an incipient phase, recordings showed promising results regarding the behaviour of recycled-PET thermal wadding used for insulation and indoor comfort conditions.

Life cycle cost considerations in project appraisals of collision-free roads

In the last decade, many single carriageway roads in Sweden have been converted to collision-free roads as a cost-effective alternative to conventional motorways. Investigations have concluded that the road type has been successful in reducing the number of fatal accidents, despite increased operation and maintenance costs. In recent years, the focus has shifted to converting narrower roads which are anticipated to further increase operation and maintenance cost but also complicate traffic management during road works. There are concerns that when life cycle cost is considered in the investment assessment the socioeconomic profitability could be reduced. This article examines this issue by first assessing changes in costs for operation and maintenance using a life cycle cost analysis approach applied on a case study. The results from the analysis were thereafter integrated into a cost–benefit analysis to assess changes in costs in relation to benefits in improved traffic safety and travel time. The analysis indicated profitability even with substantial increase in operation, maintenance and road user work zone costs. Results are discussed from project implementation and road management perspectives.

생애주기비용과 성능을 고려한 생태복원 공법 가치분석 - 습식 비탈면 기반재를 사례로 -

환경을 훼손하지 않는 경제 성장을 위하여 건설부문의 비용 절감 및 품질 향상의 요구가 커지면서 VE/LCC 분석기법의 활용이 증가되는 추세이다. 본 연구는 생애주기비용과 성능 분석을 고려한 비탈면 생태복원 공법의 가치 분석을 목적으로 수행되었으며 비탈면 생태복원 시공조건을 경사도와 기반조건으로 3가지 조건을 나누고 각 조건별로 비탈면 생태복원 공법 3가지를 선정하여 총 9가지 조건별로 생애주기비용 분석과 성능 분석을 통하여 가치 분석을 실시하였다. 비탈면의 경사도와 기반조건에 따라 조건 1은 경사도 1:1.2 이하, 일반토사이고, 조건 2는 경사도 1:1.0 이하, 리핑암이다. 조건 3은 경사도 1:0.7 이하, 연암 및 발파암이다. 생애주기비용과 성능 분석 결과를 바탕으로 가치 분석을 한 결과, 조건1에서 B공법 108.4점, A공법 90.3점, C공법 45.8점 순으로 나타났으며, 조건 2에서는 A공법 89.1점, B공법 47.5점, C공법 47.0점 순으로 나타났고, 조건 3에서는 A공법 89.1점, B공법 55.4점, C공법 40.2점 순으로 나타나, 조건 1에서는 B공법이 높았으나, 조건 2, 3에서는 A공법의 점수가 높았다. 본 연구결과를 토대로 생애주기비용과 성능 분석을 고려하여 비탈면 생태복원 사업의 원가절감 및 품질 향상을 도모할 수 있는 합리적인 의사결정에 사용될 수 있을 것이다. In order to save costs and enhance quality in construction without damaging the environment, the VE/LCC analysis method is increasingly used. This study was carried out to conduct a value analysis for the ecological restoration of a slope considering life cycle cost and performance. The construction conditions were classified into three types(A, B, C) according to the condition of each base. Three construction methods for slope ecological restoration were selected by each condition. Eventually, a value analysis was conducted for total nine conditions by analyzing the life cycle cost and performance. The gradient of slope and base of Condition 1 were below 1:1.2 and general soil, while condition 2 and 3 were below 1:1.0(reaping rock) and below 1:0.7(soft rock, blasted rock), respectively. A value analysis was conducted based on the value estimated via life cycle cost and performance analysis. The result showed that the B construction method had the highest value in Condition 1 as it showed 108.4, while A and C showed 90.3 and 45.8, respectively. When it comes to Condition 2, Construction Method A indicated the highest value as it showed 89.1(B: 47.5, C: 47.0). In Condition 3, Construction Method A(89.1) was the highest, while B and C showed 55.4 and 40.2, respectively. Based on the result of this study, in order to make a reasonable decision that can enhance quality and reduce costs in slope ecological restoration, the slope ecological restoration method must be reviewed in consideration of life cycle cost and performance.

Life-Cycle Assessment for Construction of Sustainable Infrastructure

AbstractThe architecture-engineering-construction (AEC) industry faces increasing demands on its projects while budgets appear to be shrinking. Building owners and operators seem to want their buildings to do more for less cost. Although this may seem counterintuitive, it aligns nicely with a sustainable-architecture approach of less is more. Moreover, in a shift from exclusively considering first costs for a project, the AEC industry seems to be moving in the direction of life-cycle cost considerations, furthering the opportunity for a more sustainable built environment. Often sustainable is synonymous with achieving certification [e.g., Leadership in Energy and Environmental Design (LEED) and Infrastructure Voluntary Evaluation Sustainability Tool (INVEST) certification]. Whereas the authors acknowledge that certification can improve particular aspects of sustainability, it is necessary to take a broader approach and consider economic, environmental, and social dimensions of sustainability. In this pape...

基于UMM的主设备运维策略研究

介绍了目前南网运维策略现状，并分析了现在运维策略中存在的弊端。针对此，本文提出了一种考虑设备全寿命周期成本，基于贝叶斯网络模型的不确定多阶段多目标运维决策模型，并给出了模型求解过程。最后通过建立GIS的UMM (uncertainty)运维策略模型，制定最佳的运维策略，验证所提出UMM决策模型的有效性。 In this paper the existing situation of the operation maintenance strategy of gird main equipment is presented and the problems of traditional operation maintenance strategy are analyzed. A new model based on uncertainty multi- stage and multi-object by Bayesian network is presented in this paper, which is for making operation maintenance strategy with the consideration of life cycle cost. In the end a GIS example proves the UMM model’s practical applications.

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.

Corrosion Initiation Projection for Reinforced Concrete Exposed to Chlorides: Part 2—Corrosion-Resistant Bars

Abstract A companion paper (Part 1) introduced a protocol whereby time-to-corrosion, Ti, of reinforcing steel in concrete exposed to chlorides is calculated as a distributed, rather than discrete, parameter. The method consists of, first, considering that identically exposed, electrochemically independent elements comprise the concrete of interest and, second, inputting distribution functions for surface Cl− concentration (Cs), the effective diffusion coefficient (D), concrete cover over the reinforcement (x), and the critical Cl− concentration threshold to initiate corrosion (CT) into a governing equation from which the fraction of elements that have initiated corrosion is calculated for a specific exposure time. Upon repeating the calculation for different times, a cumulative distribution function (CDF) plot of Ti is constructed. In the Part 1 paper, the protocol was applied to black bar (BB) reinforcement; however, with advent of life-cycle cost considerations and specified bridge design lives of 75 ye...

Building-Volume Designs with Optimal Life-Cycle Costs

This report provides a detailed overview of the building-volume optimization (BVO) model. It allows for insights into elements that comprise the BVO model, describes its setup as an optimization tool for design and tests its possibilities through exemplary runs. It includes the description of all life-cycle cost (LCC) members involved and explains the implemented optimization process approach. It also provides a perspective regarding the sensitivity and consequences of the BVO model. Serving as decision-support for designers the model qualifies as a practice-oriented application during the early design stage. Test results indicate that LCC considerations can significantly affect building-volume designs during this stage. Therefore, the introduction of cost objectives to the building-volume design represents a valuable approach. Enabling for their inclusion, design issues referring to estimated building performances, are capable of improvement before design finalization. Especially comparisons between initial and operational costs imply that, with increasing life-cycle periods, the impact of operational costs on shaping building-volume design is continuously growing.

Seasonal and Lifecycle Cost Considerations in Evaluating Beneficial Utilization of Digester Gas

Seasonal and Lifecycle Cost Considerations in Evaluating Beneficial Utilization of Digester Gas

Risk-Based Ship Design: A Framework for the Carriage of Dangerous Goods by Sea

Risk-based ship design is a formalised methodology that integrates systematically risk assessment in the design process with prevention/reduction of risk (to life, property and the environment) embedded as a design objective, alongside “conventional” design objectives (such as speed, capacity, etc). This paper aims at providing a comprehensive overview of the basic elements of the methodology, including reference to applicable risk and other design criteria. The approach goes beyond other formal procedures for risk quantification, risk assessment and risk management existent in various contexts (for instance the Formal Safety Assessment for developing rules, the Safety Case approach for specific design/operational solutions), in that it takes into account mechanisms for trade-offs between safety and other design factors by utilising overlaps between performance, life-cycle cost considerations, functionality and safety at parameter level. The paper also exemplifies the use of the methodology by presenting a framework for application for the case of carriage of dangerous goods by sea.

A techno-economic probabilistic approach to superheater lifetime determination

In the commonly used approach, the lifetime of a superheater is estimated by characteristic values of the production parameters and the operating conditions. In this approach, a lower bound for a superheater lifetime is based on some arbitrary safety factor that does not necessarily reflect real life, where unexpected failures do occur. The method proposed here suggests coping with this reality, by employing a techno-economic probabilistic approach. It comprises the following two models: • A probabilistic time to failure evaluation model that considers the variability of the lifetime determining parameters. • A model to optimise values of technical parameters and operating conditions and to determine a superheater’s optimal replacement policy, based on life cycle cost considerations. The proposed probabilistic time to failure evaluation model can help to identify the most influential parameters for planning for a minimal probability of failure. It is applied to a unique problematic steel T22 superheater of rather specific parameters: corrosion rate, the Larson Miller Parameter (LMP), diameter and wall thickness. Sensitivity analysis has shown that the dominant factor affecting variation in superheater lifetime is the variation in the LMP, while the effect of the other parameters is quite marginal. Decreasing the standard deviation of the LMP (by keeping a more uniform material) lowered the probability of failure. This resulted in a practical recommendation to perform periodical checks of the parameter wall thickness. We also tested the effect of changing the nominal values of these parameters on the lifetime distribution. Hence, we suggest that the selection of the nominal values should be based on life cycle cost considerations; and propose a model to calculate, for any given combination, the average life cycle cost. The latter model, the optimal parameters combination model, optimises the combination of changes in all the superheater’s parameters by minimising the average life cycle cost associated with the superheater. Demonstrating the usefulness of the proposed approach, in a problematic case, suggests that it can be beneficially employed in the more general case whenever the planned lifetime of a design is threatened.

Optimal seismic design of steel frame buildings based on life cycle cost considerations

AbstractA multi‐objective optimization procedure is presented for designing steel moment resisting frame buildings within a performance‐based seismic design framework. Life cycle costs are considered by treating the initial material costs and lifetime seismic damage costs as two separate objectives. Practical design/construction complexity, important but difficult to be included in initial cost analysis, is taken into due account by a proposed diversity index as another objective. Structural members are selected from a database of commercially available wide flange steel sections. Current seismic design criteria (AISC‐LRFD seismic provisions and 1997 NEHRP provisions) are used to check the validity of any design alternative. Seismic performance, in terms of the maximum inter‐storey drift ratio, of a code‐verified design is evaluated using an equivalent single‐degree‐of‐freedom system obtained through a static pushover analysis of the original multi‐degree‐of‐freedom frame building. A simple genetic algorithm code is used to find a Pareto optimal design set. A numerical example of designing a five‐storey perimeter steel frame building is provided using the proposed procedure. It is found that a wide range of valid design alternatives exists, from which a decision maker selects the one that balances different objectives in the most preferred way. Copyright © 2003 John Wiley & Sons, Ltd.

Cost optimal design of R/C buildings

A systematic approach is proposed for evaluating the cost-effectiveness of existing or proposed design criteria from the standpoint of life-cycle cost consideration. A series of alternative designs of a model structure representing a class of R/C buildings would be developed following an existing code procedure, except that the code requirements or parameters will be varied for the alternative designs so that a suite of different structures will be obtained each with a different level of safety or reliability. For each of the designed structures, the probability of exceeding the various damage levels under a given earthquake intensity may be calculated. Aggregating and integrating all the cost components with the damage probability density functions for each of the designed structures, as well as with the probabilities of all possible earthquake intensities over a given life will yield the expected life-cycle costs for the respective structures as a function of structural reliability. From these results, the design with the minimum expected life-cycle cost may then be identified; its underlying safety or reliability can also be determined. The approach is illustrated for a class of reinforced concrete buildings under earthquake loading.

Life cycle cost: an individual consumer’s perspective

Pricing of certain items (mainly durables) involves two components: purchase cost and maintenance cost. The interaction between both cost components is commonly referred to by the term Life Cycle Cost (LCC). Previous studies indicate that potential buyers are not always aware of the adverse financial outcomes that may stem from certain selections where alternative LCC items are considered. Nevertheless, all these indications are rather indirect. The present study examines directly both the awareness of potential buyers to LCC considerations as well as their capability of handling 'properly' LCC decisions. In this regard hypotheses are formulated and tested against experimental data that simulate both durable and non-durable purchase situations. © 1997 John Wiley & Sons, Ltd.

The Series 320 Radar: Three-Dimensional Air Surveillance for the 1980s

Air surveillance radars for this decade will be required to provide reliable target location and trajectory information in height as well as the conventional geographical coordinates. These threedimensional radars will perform this task in spite of adverse environmental conditions such as ground, airborne clutter, and electromagnetic interference. The use of powerful false-alarm control processing allows automatic target detection and remoting of target information without overloading central processing capabilities. The technological evolution of the past decade has allowed sophisticated analysis, antenna/receiver/transmitter design, and signal/data processing techniques to be applied to the next generation of practical production radar systems. These radars will meet more severe performance requirements and will be significantly improved in terms of reliability, maintainability, and life cycle cost considerations. A candidate radar to fulfill the air surveillance role of this decade is the Series 320 radar manufactured by ITT Gilfillan.

Economic evaluation and optimization of solar heating systems

A procedure is developed for assessing the economic viability of a solar heating system in terms of the life cycle savings of a solar heating system over a conventional heating system. The life cycle savings is expressed in a generalized formby introducing two economic parameters, P 1 and P 2, which relate all life cycle cost considerations to the first year fuel cost or the initial solar system investment cost. Using the generalized life cycle savings equation, a method is developed for calculating the solar heating system design which maximizes the life cycle savings. A similar method is developed for determining the set of economic conditions at which the optimal solar heating system design is just competitive with the conventional heating system. The results of these optimization methods can be presented in tabular or graphical form. The sensitivity of the economic evaluation and optimization calculations to uncertainties in constituent thermal and economic variables is also investigated.