Multiple drive belt conveyors are being increasingly incorporated in mining plans worldwide because of their high economic performance and the ease of moving these installations around, especially in underground mines. A typical modern multi-drive conveyor system consists of one or more intermediate drive stations positioned along the upper stretch of the conveyor and a single drive station situated in the lower stretch. Despite the acknowledged cost saving potential of the multiple drive technology, no previous work was reported on the methodology to realize a cost-effective design of multi-drive belt conveyors. This study investigates a design approach for multiple drive belt conveyors with the objective to achieve the lowest life cycle cost of multi-drive belt conveyors for a specified material transport task. For this purpose, an optimization model for the cost-effective design of multi-drive conveyor systems is formulated on the basis of the recommendations of the DIN 22101 and SANS 1313 standards. For a given number of intermediate drive stations, the proposed model optimizes a set of design parameters so that the minimum equivalent annual cost of a conveyor can be attained whilst handling the transport requirements and design conditions. The conveyor parameters optimized in this study are the rated powers of motors, the rated torques of gear reducers, the diameters and wrap angles of drive pulleys, the belt width, the belt speed, the lengths of the belt sections not nestled between drive pulleys, the spacings between idler rolls and the shell diameters and shaft diameters of idler rolls. For benchmark analysis purposes, a similar optimization model is also developed for the single drive technology. Described as mixed integer nonlinear programming (MINLP) problems, the two optimization models are solved using the MIDACO solver embedded in the MATLAB environment. The results of this study show the validity and effectiveness of the design model proposed for multi-drive belt conveyors. The results also indicate that the multiple drive technology is more beneficial for the conveying over long distances. The impact of the possible instability of inflation throughout the project lifetime is also investigated through three hypothetical scenarios, which involve a fixed inflation rate, a higher fluctuating inflation rate and a lower fluctuating inflation rate, respectively. The results of this sensitivity analysis show that the most cost-effective multi-drive belt conveyors obtained under a fixed inflation rate is robust enough against limited fluctuations of this parameter. / Dissertation (MEng)--University of Pretoria, 2017. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted

The MIND optimization method is a tool for life cycle cost minimization of a flexible range of industrial energy systems. It can be used in analyses of energy systems in response to changes within the system, changes of the boundary conditions and synthesis of energy systems.  In analysing industrial energy systems there are a variety of issues to consider in finding the best way of production. Both the energy supply part and the energy demand part is of great significance. The structure of the energy supply part is often decided on economic terms such as fixed costs, fuel prices or energy tariffs but also on availability. The energy demand is depending on the technology employed and the layout of the system. A change to new technology or recondition of old equipment may as well as alterations in the production schedule give considerable overall savings.  In order to comprise all aspects in the analysis it is essential that the optimization method can handle:  all occurring flows in the energy system,  time-dependent components and conditions,  non-linearities.  A change regarding the production schedule, kind of energy or renewal of process equipment may cause a change of material and energy flows as well as a change of the interaction between them. Since industry as a rule has a production goal to fulfil it is necessary to represent both material and energy flows in the calculations.  Time dependency for components indicates that process equipment must be represented in a way that allows different process routes to be chosen within the industrial system. Changes in boundary conditions, such as varying energy rates or climatic conditions, will also have to be represented. This implies that the system has to be represented with a proper time division.  It is also necessary to let flows pass between time steps to be able to consider storage of both material and energy.   Optimization of industrial energy systems at the component level involves non-linear relationships, such as energy demand functions and investment cost functions. It is important to use the proper level of accuracy in the representation of equipment units. If non-linear relationships are not included there may be considerable errors involved. The accuracy of representation must be chosen for each industrial system to be optimized.  These demands can be met in optimization with mixed integer linear programming. Non-linear relationships can be approximated with step functions and piecewise linear segments giving the opportunity to optimize all levels of energy systems.  The objective of the optimization is to minimize the life cycle cost of the studied energy system. The life cycle cost includes both fixed and variable costs.  Two applications are presented to show the flexibility of the MIND method, heat treating processes in the engineering industry and milk processing in a dairy.

Public buildings and other public facilities are essential for the functioning and quality of life in modern societies, but they also frequently have a significant negative impact on the natural environment. Public agencies, with their large portfolios of facilities, have faced considerable challenges in recent years in minimizing their negative environmental impacts and energy consumption and coping with shortages of financial capital to invest in new facilities and operate and maintain existing ones, while still meeting their mission goals. These range from the need to provide a quality workplace for their staff to providing a public service and long term benefits to the public. The concept of green building has emerged as a set of objectives and practices designed to reduce negative environment impacts and other challenges while enhancing the functionality of built facilities. However, the prevailing belief related to implementing green building is that incorporating Green Building Strategies and Technologies (GBSTs) increases the initial cost of constructing a facility while potentially reducing its life cycle costs. Thus, this research deals with optimizing the design of individual facilities to balance the initial cost investment for GBSTs versus their potential Life Cycle Cost (LCC) savings without the need to conduct detailed life cycle cost analysis during the early capital planning and budget phases in public sector projects. The purpose of this study is to develop an approach for modeling the general relationship between investments in initial costs versus savings in LCCs involved in implementing green building strategies in public capital projects. To address the research question, this study developed multiple regression models to identify the relationships between GBSTs and their initial cost premiums, operating costs, and LCCs. The multiple regression models include dummy variables because this is a convenient way of applying a single regression equation to represent several nominal variables, which here consist of initial, operating, maintenance, and repair and replacement costs, and ordinal variables, which in this case are the GBST alternatives considered. These new regression models can be used to identify the relationship between GBST alternatives, initial cost premiums, annual operating costs and LCC in the earliest stage of a project, when public agencies are at the capital planning and budgeting stages of facility development, without necessarily needing to know the precise details of design and implementation for a particular building. In addition, this study also proposes and tests a method to generate all the necessary cost data based on building performance models and industry accepted standard cost data. This statistical approach can easily be extended to accommodate additional GBSTs that were not included in this study to identify the relationship between their initial cost premium and their potential LCC saving at the earliest stage of facility development. In addition, this approach will be a useful tool for other institutional facility owners who manage large facility portfolios with significant annual facility investments and over time should help them minimize the environmental impacts caused by their facilities. / Ph. D.

Life Cycle Cost Analysis (LCCA) forms an important part of asset management practices and provides an informed decision support. The holistic nature of LCCA includes life cycle assessment (LCA) as an important component alongside economic life cycle cost analysis. The drinking water industry is right now lacking a reliable cost data structure which will ensure that all the utilities capture the same set of cost data. Also, models and tools currently available in the academia and industry are purely deterministic in nature and do not cater to uncertainty in the data. This study provides a framework for a holistic life cycle cost analysis tool which will help drinking water utilities to prioritize the activities and optimize the cost spending of the utility. The methodology includes the development of a cost data structure, a life cycle cost analysis and a life cycle assessment model in the form of an excel spreadsheet. The LCCA model has the capability to compare different pipe materials, installation, condition assessment, rehabilitation and replacement technologies. Whereas, LCA model can compare different pipe materials based on greenhouse gas emissions calculations. The final step of the methodology includes piloting the model with data from utility A. The analysis has been shown in the form of three case studies - comparison of two pipe materials, two pipe installation technologies and two pipe rehabilitation technologies. The case studies provide results in the form of comparison of total life cycle costs for different alternatives and hence a better alternative can be chosen. / Master of Science

Reinforced concrete (RC) bridge decks are exposed to chlorides from deicing salts. Chloride ingress in RC initiates corrosion of the reinforcing steel. The high costs of corrosion have sparked interest in service life design of bridge decks. This thesis characterized the exposure conditions of Virginia, including temperature and surface chloride concentration, as well as Virginia concrete mix properties, including initial chloride concentration and chloride migration coefficient. The service life estimations for a case study bridge in Virginia from three service life models were compared. The first model is based on the fib Bulletin 34 Model Code for Service Life Design, the second is a finite element solution of the fib Bulletin, and the third accounts for a time-, temperature-, moisture-, and concentration-dependent apparent diffusion coefficient. A sensitivity analysis was completed on the three models showing that the most important variables in these models are the aging coefficient and surface chloride concentration. Corresponding life cycle cost analyses were completed for plain and corrosion resistant reinforcing steel. This thesis showed that the error function solution underestimates chloride ingress. The life cycle cost analysis of plain and corrosion resistant reinforcing steels show that overestimation of service life leads to underestimation of life cycle costs. / Master of Science

I denna rapport har det utförts två fallstudier från två olika vindkraftsanläggningar och med hjälp av en utarbetad modell har livscykelkostnaderna jämförts för de två fallstudierna.Resultatet visade att livscykelkostnaden per producerad kWh sjunker allteftersom den installerade effekten blir högre.Kostnadsmodellen som utarbetats och tillämpats för resultaten har visat sig ha hög verifierbarhet då resultaten har varit jämförbara med litterära studier. / In this report, conducted two case studies from two wind farms and using an elaborate model, life cycle costs compared to the two case studies.The results showed that the lifecycle cost per kWh decreases as the installed power increases.Cost model as developed and applied to generate the reported results have been generated in the results that are comparable to literary studies.

Life Cycle Cost, often abbreviated as LCC, is a common tool for comparing the total cost of different alternatives, such as heating and cooling methods. Common heating and cooling methods in Sweden are geothermal energy, district heating and district cooling. This report aims to evaluate how different heating and cooling methods differ from each other while being applied on three different types of buildings, using selected LCC-models. Information about the selected LCC-models wasretrieved from each separate model and its website. Reports and agencies were used as sources for information about the heating and cooling methods. Tendersby established energy companies in Sweden were used as input data to form different alternatives for each building. From the comparison between the selected LCC-models, both similarities and differences were identified. The differences vary both in scale and how they affect the result. Nonetheless two of the models show the same results for some of the alternatives. In order to approximate the environmental effects for each heating and cooling method, carbon dioxide emissions were compared. The conclusion of this report is that while there are significant differences between the different LCC-models, the results only differ marginally for most models. / Life Cycle Cost, ofta förkortadsom LCC, är ett vanligt använt verktyg vid jämförelse av olika alternativs, exempelvis olika uppvärmnings- och kylmetoder, totala livscykelkostnad. I Sverige är vanliga uppvärmnings- och kylmetoder bergvärme, fjärrvärme och fjärrkyla. Denna rapport syftar till att med hjälp av utvalda LCC-modeller utvärdera hur dessa olika metoder skiljer sig för olika typfall, samt att redogöra för vilka skillnader det finns mellan de utvalda LCC-modellerna. De typfall som undersöktes var tre olika fastigheter med varierande storlek och alternativ. Information om de valda LCC-modellerna hämtades från respektive modell samt vid behov från tillhörande hemsida. Olika rapporter och myndigheter ligger till grund för information för hur de olika uppvärmnings- och kylmetoderna fungerar. Indata för LCC-beräkningarna inhämtades från offerter givna av etablerade energiföretag i Sverige. Genom rena jämförelser mellan de valda LCC-modellerna hittades både likheter och skillnader. Skillnadernas inverkan varierar i både grad och vilken effekt de har på resultaten. Däremot får två av modellerna samma resultat för vissa typfall. För att uppskatta miljöpåverkan jämfördes även typfallens koldioxidutsläpp för de olika uppvärmnings- och kylmetoderna. Slutsatser som kan dras från studien är att det finns klara skillnader mellan olika LCC- modeller, men resultaten skiljer sig ofta endast marginellt.

Increasing freshwater scarcity is making reclamation of wastewater effluent more economically attractive as a means of preserving freshwater resources. The use of an integrated membrane system (IMS), the combination of micro/ultra-filtration (MF/UF) followed by reverse osmosis (RO) membranes, represents a key process for municipal wastewater reuse. A major drawback of such systems is the fouling of both the MF/UF and RO membranes. The water to be treated by the IMS system varies from one wastewater treatment plant (WWTP) to another, and its fouling propensity changes correspondingly. It is thus preferable to conduct pilot trials before implementing a full-scale plant. This thesis aims to look at the sustainability of IMS technology dedicated to indirect potable reuse (IPR) in terms of fouling minimisation and cost via a 600 m3 .d- 1 pilot plant. Wastewater reuse plants, using IMS, as well as statistical methods for membrane optimisation were reviewed. Box-Behnken design was used to define optimum operating envelopes of the pilot plant for both the microfiltration and the reverse osmosis in terms of fouling minimisation. Same statistical method was used to enhance the efficiency of the MF cleaning-in place through bench-scale test. Data from the pilot plant MF process allow to determine relationship between reversible and irreversible fouling, and operating parameters and feed water quality. Life cycle cost analysis (LCCA) of the both trains (MF/RO/AOP and MF/AOP) of the pilot plant was performed and compared with the LCCA of two full-scale plant.

<div> <p>The residential building sector is one of the most energy intensive sectors in today’s civilization. With population growth and a rise in number of homeowners the effect is bound to worsen. A wave of green and sustainable strategies is on the rise hoping to moderate some of the negative effect on the environment. From embracing renewable sources of energy as an alternative to fossil fuels, to improving existing home systems to become more efficient, the construction industry is evolving into becoming more energy conscious. One of the biggest obstacles to this wave is a lack of awareness and a fear of initial costs among contractors, homeowners and clients alike. This research will use Life Cycle Cost Analysis on a varying combination of residential energy systems and the researcher hopes to establish the trade-off between initial investment and long-term benefits. The case being considered is a residence located in Indiana, US. Using past and current utility bills and energy simulation data of different energy consuming systems in the residence over its lifetime, economic models are generated. This research establishes that a combination of passive and active energy conservation measures results in the lowest life cycle cost. The study will be beneficial for further research and as a framework for residential life cycle cost analysis.</p></div>

A sustentabilidade pode ser uma realidade para a concepção e construção de uma rodovia, especialmente quanto ao pavimento. Dentro deste contexto, a análise do ciclo de vida - LCA (Life Cycle Analysis) e a análise do custo do ciclo de vida - LCCA (Life Cycle Cost Analysis) dos pavimentos são formas de prover meios para avaliar aspectos relativos à sustentabilidade de uma solução de pavimentação, seja no setor ambiental ou econômico. Na pesquisa apresentada, essas ferramentas são utilizadas para identificar os compromissos em tomada de decisão, uma vez que permitem a apreciação de indicadores de sustentabilidade e viabilidade de investimento, a partir do momento da produção das matérias-primas, até implantação do pavimento, manutenção, conservação e uso da rodovia. Portanto, nessa pesquisa foram avaliadas e comparadas três estruturas típicas de pavimento (flexível, semi-rígido e rígido) propostas para uma rodovia que se encontra em fase de implantação. Após verificação e comparação dos dados obtidos foi feita a integração desses resultados sob âmbito de sustentabilidade e viabilidade de implementação, através do método multicritério AHP (Analytic Hierarchy Process). Tal integração permitiu uma avaliação analítica de indicadores, por meio da verificação das emissões de CO2 equivalentes, e também através da constatação do VPL (valor presente líquido) para cada alternativa considerada. De maneira geral, sob as condições estabelecidas nesta pesquisa, os resultados permitiram observar, por exemplo, qual estrutura levaria a uma maior liberação de CO2 na atmosfera e qual pavimento apresentaria viabilidade de investimento menos atrativa, o que poderia auxiliar na tomada de decisão quanto à estrutura a ser adotada naquele projeto. / Sustainability can be a reality for the design and construction of a highway, especially considering the pavement. Within this context, Life Cycle Analysis (LCA) and Life Cycle Cost Analysis (LCCA) of pavements may provide means to evaluate aspects related to the sustainability of a solution, both in the environmental or economic sectors. In the presented research, these tools are used to identify the commitments in decision making, since they allow the evaluation of sustainability indicators and feasibility of investment, since production of raw materials, until the pavement construction, maintenance, conservation and highway operation. Therefore, in this research, three typical pavement structures (flexible, semi-rigid and rigid) were proposed and compared (undergoing project). After verification and comparison of the obtained data, the integration of LCA and LCCA under sustainability and feasibility aspects was done through the AHP (Analytic Hierarchy Process) multi-criteria method. This integration allowed an analytical evaluation of indicators, through the verification of the equivalent CO2 emissions, and also through the verification of the NPV (net present value) for each alternative considered. In general, under the conditions established in this research, the results showed, for example, which structure would lead to a higher release of CO2 into the atmosphere and which pavement would present less attractive investment feasibility, which could help in decision making of which pavement structure could be adopted in that project.