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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Development of a supervisory system for maintaining the performance of remote energy management systems / Johan Nicolaas du Plessis

Du Plessis, Johan Nicolaas January 2014 (has links)
Energy services companies (ESCOs) typically implement energy management systems (EMSs) as part of Demand-Side Management (DSM) projects on South African mines. After DSM project completion, the mine becomes responsible for maintaining the performance of the EMS. Due to a lack of experience in using specialised EMSs, mines typically contract ESCOs for EMS maintenance. However, maintaining a large number of EMSs remotely is a resource-intensive task because of time wasted on daily monitoring and travelling to perform on-site maintenance. For the same reason, remote maintenance technologies have become widely used to maintain cellular devices, vehicles and industrial equipment. Mine EMSs typically control production-critical systems that in turn ensure safe working conditions underground. EMSs execute highly specialised control philosophies to achieve electrical energy management, while ensuring safe and productive system operation. None of the work done on remote maintenance, however, provides an integrated solution to maintain the performance of a growing number of these specialised EMSs. As part of this study, a supervisory system was developed to optimise remote maintenance of different EMS technologies. The supervisory system builds on the fundamentals of existing remote maintenance technologies, complemented by comprehensive diagnostics of specialised EMS technologies. This is possible through automated diagnostics of EMS components, the control philosophy and overall EMS performance. Maintenance management forms part of the supervisory system to ensure that maintenance is performed with optimal efficiency. A system implementation was executed to prove the feasibility of the supervisory system. The functional operation of the system was verified with pre-set scenarios that simulated day-to-day operation and common fault diagnostic events. As part of the case studies conducted for this thesis, the supervisory system was integrated with three distinct EMS technologies implemented on South African mines. To support the results of these case studies, the system validation was extended through integrations with seven additional EMSs. For the first time, a supervisory assessed the condition of the EMS components, the control philosophy and DSM performance comprehensively. The results (obtained over a period of more than six months) indicated that the average operational availability of EMS components improved from 90% to 97%. The average EMS performance improved from 1.8 MW to 2.5 MW, an improvement of 39%. The resulting electricity cost reduction achieved on the case studies accumulated to approximately R6 million during the respective assessment periods. The supervisory system facilitated efficient EMS maintenance, thus reducing the risk of unsafe working conditions and production interruptions. The system also allowed maintenance personnel to improve the diagnostic process continually, thus aligning with the standards documented in ISO 50001:2011 (ISO, 2011) regarding continual improvement of electrical energy management initiatives. The new supervisory system is scalable, thus an ESCO can maintain the performance of a growing number of EMSs remotely. Results of this study support further supervisory system integration with compatible EMS technologies, and expansion to new EMS technologies. The modular design of the supervisory system provides a basis for the development of a cross-industry platform for maintaining EMS performance. / PhD (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2014
62

Improving DSM project implementation and sustainability through ISO standards / Mariska van Heerden

Van Heerden, Mariska January 2014 (has links)
South African industries are challenged with above inflation electricity tariffs which may affect their competitiveness within their relative markets. In order to successfully manage these rising electricity costs and ensuing top market competition, a well organised demand side management (DSM) strategy must be implemented. Energy service companies (ESCos) have been assisting Eskom, South Africa’s leading electricity utility, in managing energy projects around the country. These DSM projects have introduced remarkable electricity and cost savings. However, the need for a sustainable energy management system (EnMS) within these projects does exist. This dissertation illustrates and discusses an EnMS designed to achieve maximum possible energy savings performances. The ISO 9 001 (quality management), ISO 14 001 (environmental management) and ISO 50 001 (energy management) standards were integrated for the development and implementation of this system. It provides a framework for project engineers and industrial clients to apply before, during and after project implementation. The use of the Plan-Do-Check-Act (PDCA) cycle will be applied throughout the dissertation. The PDCA cycle follows basic steps recommended by the relevant ISO standards. This cycle emphasises the concept of continual improvement. The developed EnMS was successfully implemented on various DSM projects. This selection includes previously maintained and new implemented projects. An analysis between the implementation and post- implementation performances supports the achieved results. The results of the case studies are presented in this dissertation. This dissertation illustrates that the continual improvement of an ISO based EnMS will result in a sustainable increase in electricity savings. An overall increase in project quality can be defined and measured according to the electricity consumptions and electricity cost savings. These electricity cost savings from the selected projects resulted to nearly R18 million during project implementation. A total amount of R52 million was already saved during the maintenance phase of 2014. This cost savings only reflect the results of the eight selected projects for the first eight months in 2014. The EnMS explained in this dissertation indicates that a continually controlled framework can improve the quality of DSM project implementation and sustainability. With the flexibility of changing the system according to impulsive constraints and client demands, the system can be used with various DSM projects. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
63

Developing a dynamic control system for mine compressed air networks / Schalk Willem van Heerden

Van Heerden, Schalk Willem January 2014 (has links)
Mines in general, make use of compressed air systems for daily operational activities. Compressed air on mines is traditionally distributed in two typical fashions. Firstly, direct pipe feed systems for single shafts or compressed air ring networks where multiple shafts are supplied with compressed air from an integral system. These compressed air networks make use of number compressors feeding the ring from various locations in the network. While mines have sophisticated control systems to control these compressors they are not dynamic. Compressors are selected on static priorities for a chosen time period of the day. While this is acceptable for some days it is not always the ideal solution. The compressed air demand of the ring is dynamic and it is difficult to estimate the future need of the system. The Dynamic Compressor Selector (DCS) is described as a solution to this problem. DCS is a computer based control system featuring a Graphical User Interface (GUI). The aim of DCS is to dynamically calculate a control pressure set-point, given the demand for compressed air as well as choose the optimal compressors to supply the given compressed air. This will reduce the power requirement of the compressed air ring as well as reduce compressor cycling. DCS was implemented and tested on a single mine compressed air system. Achieved results were 1.8 MW in electricity savings as well as the added benefit of reduced cycling. This saving results in a cost saving of R3.7 million per annum. The problems and shortfalls of the system are also discussed as well as possible future directions for moving forward. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2014
64

Implementing DSM interventions on water reticulation systems of marginal deep level mines / Adriaan Petrus van Niekerk

Van Niekerk, Adriaan Petrus January 2014 (has links)
Because of a continuous increase in the demand for electricity in South Africa the country’s largest electricity utility (Eskom) has been under strain to provide electricity. An expansion programme to generate more electricity has caused a continuous increase in utility costs. Steep electricity tariff increases have forced large electricity consumers, such as the mining industry, to focus on energy efficiency and demand side management (DSM). More recently, large industrial action has affected the marginality of the mining industry in such a way that mining groups were forced to cut down on production cost and even sell mining shafts. A solution has to be found to improve the marginality of these mines. DSM intervention on mine water reticulation systems has shown great promise in the past and has been implemented on many South African mines with great success. Many mines with smaller systems have not been optimised because the priority of DSM intervention was to achieve the largest saving; therefore, larger systems enjoyed priority over smaller systems. This only added to the increased financial pressure on already marginal mines. In this study the operation of a mine water reticulation system will be studied to identify the most efficient DSM interventions to implement. DSM intervention on dewatering-, refrigeration- and water distribution systems will be investigated to get a better understanding of the functions of these operations. Previous project data will be analysed to create tools that would assist in the decision-making process for DSM intervention regarding saving potential, cost benefit and cost implication. This data would ultimately assist in determining a project’s payback period that is used to prioritise DSM intervention applications. A mining group will be analysed to identify possible DSM intervention potential. The systems will be investigated and the best strategy for DSM intervention will be selected. This study will conclude that it is financially feasible to implement DSM interventions on marginal mines’ dewatering systems. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014
65

A needs assessment of the market for resource efficiency and cleaner production services in the Vaal Triangle / Theunis Christoffel Botha

Botha, Theunis Christoffel January 2014 (has links)
Major energy-consuming countries implemented new laws on energy-efficiency during the course of 2013. The new energy-efficiency law make provision for a 16% reduction in energy intensity by 2015 in China. New law in the United States of America requires new fuel-economy standards. European Union law aims for a cut of 20% in energy demand for the countries forming part of the European Union. Japan, with the country's new energy strategy aims to decrease electricity demand with 10% by 2030 as stipulated in the new energy strategy. South Arica is currently experiencing a shortage in electricity generating capacity and operates within its reserve margin. The construction of new power stations is in process to address the shortage but Eskom must finance these assets by increasing the electricity tariff. Electricity prices are predicted to double from 2013 to 2017. In addition to the tariff increases, the Energy Conservation Scheme (ECS) is also planned by Eskom whereby all electricity consumers have to reduce their electricity consumption by 10% or face penalties. Energy efficiency initiatives in South Africa will help meet some of the country's social, economic, and environmental goals. These initiatives are important as they immediately tackle the problem of electricity shortages and are a cost-effective way of increasing available electricity supply. The aim of this study was to determine the need for businesses in the Vaal Triangle to be resource efficient and practice clean production in order to be able to capitalise on that need. With the current knowledge and technology available, Resource Efficiency and Cleaner Production (RECP) will prove to be a future necessity for industry. To determine the perceived readiness towards a green economy contribution is thus of importance. The study did a review on RECP, energy efficiency, supply of energy in South Africa, focus areas for energy efficiency and the benefits thereof. The study discussed energy efficiency incentive schemes and subsidisation funds available in South Africa. The study assessed the primary fields for RECP, the drivers and barriers to RECP and the willingness to participate in RECP initiatives in the Vaal Triangle. The study concluded that there exists a need in the Vaal Triangle for RECP initiatives and that there exists potential for the start of a green economy in the region. The research indicated the reaction towards RECP initiatives to be very positive in the studied region. / MBA, North-West University, Potchefstroom Campus, 2015
66

An integrated sustainability framework for environmental impact reduction in the gold mining industry/ Hendrik Gideon Brand

Brand, Hendrik Gideon January 2014 (has links)
The gold mining industry pollutes both water and air resources in numerous ways. Of these, air pollution from greenhouse gasses inducing climate change poses the highest threat to human existence, with water scarcity as a result of pollution presenting the third highest risk (Mathews, 2007; Akorede et al., 2012; Jones et al., 1988). Water pollution, indirect air pollution and direct air pollution should be mitigated for sustainable gold mining. Environmental impact reduction is achieved by the implementation of effective Environmental Management Systems (EMSs). These systems aim to achieve ISO 14001-compliance by setting targets and implementing a systematic approach to achieving these targets. However, ISO 14001-compliant systems do not ensure environmental impact reduction and give the mine no competitive edge (Hilson & Nayee, 2002). EMSs available are too generic for implementation on gold mines. Reporting on Key Performance Indicators (KPIs) on gold mines should also be improved as it is unclear exactly what values should be reported on. This is due to a general lack of an environmental reporting standard (Jones, 2010). Manpower and expertise to identify and implement projects is limited and the mines need assistance with the implementation of projects to effect resource pollution. Priority for the mines is an emphasis on production and safety rather than environmental impact reduction, so implementing projects to reduce pollution is often neglected. A novel sustainability framework is developed in this study. In this framework a database of electricity- and environmental impact reduction projects is created that can be implemented in the gold mining industry. Projects are automatically identified by monitoring key operational indicators. By involving a third party in the form of an Energy Services Company (ESCO), project funding for these sustainability projects can be attained. This novel approach to environmental impact reduction creates a situation where ESCOs implement these EMSs at a reduced cost to the mines. This reduces the cost of lowering the mine’s environmental impact, while aiding the ESCO in identifying sustainability projects. KPIs from various studies are consolidated to determine exactly what values should be reported on. These values are incorporated into a successful EMS. This allows the availability of all the necessary data for reporting to the Department of Energy (DoE) and the South African National Energy Development Institute (SANEDI) on electricity-savings. Projects are prioritised based on an integrated electricity- and environmental impact reduction payback approach. This approach allows funding options to be assessed for each project individually, based on both electricity- and environmental impact reduction advantages. This allowed the best funding option for each individual project to be determined. Automatic identification of these projects reduces the required manpower and resources to implement sustainability projects. Projects proposed by this study showed a combined energy efficiency reduction of 11.8 MW and achieved a load shift of 15.6 MW. In addition to electricity reduction, these projects also reduced the water usage by 1135 Ml per annum and the carbon dioxide equivalent production by 214 205 ton per annum. The proposed projects were effective at increasing the sustainability of gold mining. It also streamlined the implementation of these projects on gold mines. By applying this framework, sustainability improvements can now be achieved on gold mines worldwide. / PhD (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014
67

The suitability of WiFi infrastructure for occupancy sensing / Melanie Delport

Delport, Melanie January 2014 (has links)
The focus of this study was to investigate an alternative and more cost effective solution for occupancy sensing in commercial office buildings. The intended purpose of this solution is to aid in efficient energy management. The main requirements were that the proposed solution made use of existing infrastructure only, and provided a means to focus on occupant location. This research was undertaken due to current solutions making use of custom occupancy sensors that are relatively costly and troublesome to implement. These solutions focus mainly on monitoring environmental changes, and not the physical locations of the occupants themselves. Furthermore, current occupancy sensing solutions are unable to provide proximity and timing information that indicate how far an occupant is located from a specific area, or how long the occupant resided there. The research question was answered by conducting a proof of concept study with data simulated in the OMNeT++ environment in conjunction with the MiXiM framework for wireless networks. The proposed solution investigated the fidelity of existing WiFi infrastructure for occupancy sensing, this entailed the creation of a Virtual Occupancy Sensor (VOS) that implemented RSS-based localisation for an occupant’s WiFi devices. Localisation was implemented with three different location estimation techniques; these were trilateration, constrained nearest neighbour RF mapping and unconstrained nearest neighbour RF mapping. The obtained positioning data was interpreted by a developed intelligent agent that was able to transform this regular position data into relevant occupancy information. This information included a distance from office measurement and an occupancy result that can be interpreted by existing energy management systems. The accuracy and operational behaviour of the developed VOS were tested with various scenarios. Sensitivity analysis and extreme condition testing were also conducted. Results showed that the constrained nearest neighbour RF mapping approach is the most accurate, and is best suited for occupancy determination. The created VOS system can function correctly with various tested sensitivities and device loads. Furthermore results indicated that the VOS is very accurate in determining room level occupancy although the accuracy of the position coordinate estimations fluctuated considerably. The operational behaviour of the VOS could be validated for all investigated scenarios. It was determined that the developed VOS can be deemed fit for its intended purpose, and is able to give indication to occupant proximity and movement timing. The conducted research confirmed the fidelity of WiFi infrastructure for occupancy sensing, and that the developed VOS can be considered a viable and cost effective alternative to current occupancy sensing solutions. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2014
68

Development of a supervisory system for maintaining the performance of remote energy management systems / Johan Nicolaas du Plessis

Du Plessis, Johan Nicolaas January 2014 (has links)
Energy services companies (ESCOs) typically implement energy management systems (EMSs) as part of Demand-Side Management (DSM) projects on South African mines. After DSM project completion, the mine becomes responsible for maintaining the performance of the EMS. Due to a lack of experience in using specialised EMSs, mines typically contract ESCOs for EMS maintenance. However, maintaining a large number of EMSs remotely is a resource-intensive task because of time wasted on daily monitoring and travelling to perform on-site maintenance. For the same reason, remote maintenance technologies have become widely used to maintain cellular devices, vehicles and industrial equipment. Mine EMSs typically control production-critical systems that in turn ensure safe working conditions underground. EMSs execute highly specialised control philosophies to achieve electrical energy management, while ensuring safe and productive system operation. None of the work done on remote maintenance, however, provides an integrated solution to maintain the performance of a growing number of these specialised EMSs. As part of this study, a supervisory system was developed to optimise remote maintenance of different EMS technologies. The supervisory system builds on the fundamentals of existing remote maintenance technologies, complemented by comprehensive diagnostics of specialised EMS technologies. This is possible through automated diagnostics of EMS components, the control philosophy and overall EMS performance. Maintenance management forms part of the supervisory system to ensure that maintenance is performed with optimal efficiency. A system implementation was executed to prove the feasibility of the supervisory system. The functional operation of the system was verified with pre-set scenarios that simulated day-to-day operation and common fault diagnostic events. As part of the case studies conducted for this thesis, the supervisory system was integrated with three distinct EMS technologies implemented on South African mines. To support the results of these case studies, the system validation was extended through integrations with seven additional EMSs. For the first time, a supervisory assessed the condition of the EMS components, the control philosophy and DSM performance comprehensively. The results (obtained over a period of more than six months) indicated that the average operational availability of EMS components improved from 90% to 97%. The average EMS performance improved from 1.8 MW to 2.5 MW, an improvement of 39%. The resulting electricity cost reduction achieved on the case studies accumulated to approximately R6 million during the respective assessment periods. The supervisory system facilitated efficient EMS maintenance, thus reducing the risk of unsafe working conditions and production interruptions. The system also allowed maintenance personnel to improve the diagnostic process continually, thus aligning with the standards documented in ISO 50001:2011 (ISO, 2011) regarding continual improvement of electrical energy management initiatives. The new supervisory system is scalable, thus an ESCO can maintain the performance of a growing number of EMSs remotely. Results of this study support further supervisory system integration with compatible EMS technologies, and expansion to new EMS technologies. The modular design of the supervisory system provides a basis for the development of a cross-industry platform for maintaining EMS performance. / PhD (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2014
69

Improving DSM project implementation and sustainability through ISO standards / Mariska van Heerden

Van Heerden, Mariska January 2014 (has links)
South African industries are challenged with above inflation electricity tariffs which may affect their competitiveness within their relative markets. In order to successfully manage these rising electricity costs and ensuing top market competition, a well organised demand side management (DSM) strategy must be implemented. Energy service companies (ESCos) have been assisting Eskom, South Africa’s leading electricity utility, in managing energy projects around the country. These DSM projects have introduced remarkable electricity and cost savings. However, the need for a sustainable energy management system (EnMS) within these projects does exist. This dissertation illustrates and discusses an EnMS designed to achieve maximum possible energy savings performances. The ISO 9 001 (quality management), ISO 14 001 (environmental management) and ISO 50 001 (energy management) standards were integrated for the development and implementation of this system. It provides a framework for project engineers and industrial clients to apply before, during and after project implementation. The use of the Plan-Do-Check-Act (PDCA) cycle will be applied throughout the dissertation. The PDCA cycle follows basic steps recommended by the relevant ISO standards. This cycle emphasises the concept of continual improvement. The developed EnMS was successfully implemented on various DSM projects. This selection includes previously maintained and new implemented projects. An analysis between the implementation and post- implementation performances supports the achieved results. The results of the case studies are presented in this dissertation. This dissertation illustrates that the continual improvement of an ISO based EnMS will result in a sustainable increase in electricity savings. An overall increase in project quality can be defined and measured according to the electricity consumptions and electricity cost savings. These electricity cost savings from the selected projects resulted to nearly R18 million during project implementation. A total amount of R52 million was already saved during the maintenance phase of 2014. This cost savings only reflect the results of the eight selected projects for the first eight months in 2014. The EnMS explained in this dissertation indicates that a continually controlled framework can improve the quality of DSM project implementation and sustainability. With the flexibility of changing the system according to impulsive constraints and client demands, the system can be used with various DSM projects. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
70

Decision-making in the future electricity grid: home energy management, pricing design, and architecture development

Hubert, Tanguy F 27 May 2016 (has links)
As the number of autonomous decision-making entities in the electricity grid increases, it is necessary to develop (1) new decision-making capabilities embedded within the grid's control and management, and (2) new grid architecture models ensuring that both individual and system objectives are met. This work develops (1) new decision-making mechanisms enabling residential energy users and electricity providers to interact through the use of dynamic price signals, and (2) policy recommendations to facilitate the emergence of shared architecture models describing the future state of the electricity grid. In the first part, two optimization models that capture the emerging flexible consumption, storage, and generation capabilities of residential end-users are formulated. An economic dispatch model that explicitly accounts for end-users' internal dynamics is proposed. A non-iterative pricing algorithm using convex and inverse linear programming is developed to induce autonomous residential end-users to behave cooperatively and minimize the provider's generation costs. In the second part, several factors that make the development of grid architecture models necessary from a public policy standpoint are identified and discussed. The grid architecture problem is rigorously framed as both a market failure legitimizing government intervention, and a meta-problem requiring the development of non-conventional methods of solution. A policy approach drawing on the theoretical concepts of broker, boundary object and boundary organization is proposed.

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