Life-cycle cost simulation and optimization modeling for coastal structures using Markov Chains and Genetic Algorithms

PurposeThis paper proposes a new simultaneous optimization model of the industrial systems design and maintenance. This model aims to help the designer in searching for technical solutions and the product architecture by integrating the maintenance issues from the design stage. The goal is to reduce the life-cycle cost (LCC) of the studied system.Design/methodology/approachLiterature indicates that the different approaches used in the design for maintenance (DFM) methods are limited to the simultaneous characterization of the reliability and the maintainability of a multicomponent system as well as the modeling of the dynamic maintenance. This article proposes to go further in the optimization of the product, by simultaneously characterizing the design, in terms of reliability and maintainability, as well as the dynamic planning of the maintenance operations. This combinatorial characterization is performed by a two-level hybrid algorithm based on the genetic algorithms.FindingsThe proposed tool offers, depending on the life-cycle expectation, the desired availability, the desired business model (sales or rental), simulations in terms of the LCCs, and so an optimal product architecture.Research limitations/implicationsIn this article, the term “design” is limited to reliability properties, possible redundancies, component accessibility (maintainability), and levels of monitoring information.Originality/valueThis work is distinguished by the use of a hybrid optimization algorithm (two-level computation) using genetic algorithms. The first level is to identify an optimal design configuration that takes into account the LCC criterion. The second level consists in proposing a dynamic and optimal maintenance plan based on the maintenance-free operating period (MFOP) concept that takes into account certain criteria, such as replacement costs or the reliability of the system.

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Radwaste Treatment Center

Technological Engineering ◽

10.2478/teen-2013-0020 ◽

2013 ◽

Vol 10 (2) ◽

pp. 36-39

Author(s):

Petr Pospíšil

Keyword(s):

Life Cycle ◽

Life Cycle Cost ◽

Waste Treatment ◽

Treatment Center ◽

Combined Processes ◽

Waste Streams ◽

Free Standing ◽

Simulation And Optimization ◽

Treatment Equipment ◽

Treatment Technologies

Abstract Radioactive waste is produced during the NPP operation as well as the NPP dismantling and decommissioning phase. Different kinds of waste with different volumes, volume generation rates, properties and compositions have to be handled and treated according to the regulations of the corresponding country. The various waste streams arising especially during D&D activities require versatile treatment approaches to satisfy regulatory requirements and customer needs. Westinghouse has over 30 years of experience in the design, erection and commissioning of radwaste treatment equipment and facilities with special attention on waste volume reduction and minimization of secondary waste generation applied in projects, concepts and studies around the world. Minimization of the total life cycle cost for waste treatment and disposal is a key item for the application of economically viable solutions based on combined processes and integrated waste treatment systems. The ability of enhanced system design and flexible single process combination to form an optimized waste treatment center is crucial to set up the best process configuration with regard to lowest life cycle cost. Westinghouse’s experience in the field of radwaste treatment as well as the application of proven treatment technologies ensures the ability to form a customized radwaste treatment center, either integrated in an existing facility or as a new, free standing building that provides all relevant transport and handling equipment, interfaces, treatment equipment and temporary storage for waste packages. Starting with the identification of the waste streams and assessment of various treatment concepts together with the Customers, the best waste treatment concept that covers all relevant waste streams will be assessed and proposed, e.g. by using the Westinghouse Simulation and Optimization software tool. A typical example for combined waste treatment technologies is the Westinghouse Site Radwaste Treatment Facility in Sanmen (China) as well as concept variations of the SRTF for other reactors (e.g. ABWR, VVER, etc). The purpose of this paper is to provide an overview on the Westinghouse experience to design and optimize waste treatment facilities for various types of reactors under operation or post operation/D&D condition.

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An application of Markov chains to life-cycle cost analysis

Engineering Costs and Production Economics ◽

10.1016/0167-188x(90)90118-2 ◽

1988 ◽

Vol 14 (2) ◽

pp. 151-156 ◽

Cited By ~ 1

Author(s):

Evin J. Stump

Keyword(s):

Life Cycle ◽

Cost Analysis ◽

Markov Chains ◽

Life Cycle Cost ◽

Life Cycle Cost Analysis

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Design, Simulation, and Economic Optimization of an Off-Grid Photovoltaic System for Rural Electrification

Energies ◽

10.3390/en12244735 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4735 ◽

Cited By ~ 7

Author(s):

Haytham El-houari ◽

Amine Allouhi ◽

Shafiqur Rehman ◽

Mahmut Sami Buker ◽

Tarik Kousksou ◽

...

Keyword(s):

Life Cycle ◽

Life Cycle Cost ◽

Energy Demand ◽

Photovoltaic System ◽

Diesel Generator ◽

Pv System ◽

Simulation And Optimization ◽

Electricity Cost ◽

Solar Fraction ◽

Unit Energy

Access to clean and affordable energy in rural African regions can contribute greatly to social development. Hence, this article proposes the design, simulation, and optimization of a stand-alone photovoltaic system (SAPV) to provide non-polluting electrical energy based on a renewable source for a rural house located in Tazouta, Morocco. Real monthly electrical demands and hourly climatic conditions were utilized. An initial design process indicated that, with a 1080 Wp total capacity of PV modules and 670 Ah of battery storage, the proposed SAPV system was able to meet a considerable part of the dwelling load with an average solar fraction of about 79.1%. The rest of the energy demand was ensured by a diesel generator (DG). Also, a life cycle analysis of the PV system revealed that the life cycle cost is 10,195.56 USD and the unit electricity cost is 0.57 USD/kWh for an initial investment of 4858.68 USD. Thereafter, an optimum design based on Homer Pro software was carried out indicating that lower PV capacity can decrease the unit energy cost to 0.356 USD/kWh while reducing the solar fraction to 54.9%.

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