Various commercial software packages are available for simulating compressed air network operations. However, none of these software packages are able to dynamically prioritise compressor selection on large compressed air networks in the mining industry. In this dissertation, a dynamic compressor selector (DCS) will be developed that will actively and continuously monitor system demand. The software will ensure that the most suitable compressors, based on efficiency and position in the compressed air network, are always in operation. The study will be conducted at a platinum mine. Compressed air flow and pressure requirements will be maintained without compromising mine safety procedures. Significant energy savings will be realised. DCS will receive shaft pressure profiles from each of the shafts’ surface compressed air control valves. These parameters will be used to calculate and predict the compressed air demand. All pipe friction losses and leaks will be taken into account to determine the end-point pressure losses at different flow rates. DCS will then prioritise the compressors of the compressed air network based on the overall system requirement. This software combines the benefits of supply-side and demand-side management. Potential energy savings with DCS were proven and compressor cycling reduced. A DCS user-friendly interface was created to easily set up any mine’s compressed air network. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013

Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2008.

Electrical energy is commonly used in households and in industry - demand continues to rise due to economic and population growth. This requires that energy suppliers must increase their supply capacity. The result is that end–user energy costs continue to increase, therefore a growing need exists to reduce electrical energy demand in South Africa and internationally. Households account for the majority of electrical energy customers, but they only consume a fraction of the total energy supplied. The industrial sector and mines combined consume approximately 42% of the total electrical energy produced. Approximately 10% of this energy goes into compressed air production. This study focuses on methods of reducing the requirement of compressed air in industry so that the demand for electrical energy can be reduced. Many studies have focused on specific methods of reducing energy usage associated with compressed air production. These methods are categorised into methods of reducing compressed air requirements and methods of increasing compressed air supply efficiency. This study aims to combine these efforts into a single optimised solution. Although this study includes industry in general, the central focus is on the South African mining industry. Two different mining sites are considered and analysed as case studies. Methods of reducing energy required to produce compressed air were applied to each case study. Case Study 1 only allowed limited control of the compressed air system. In Case Study 2 integrated control was realised. Energy usage of compressors was reduced by 18.9% and 42.9% respectively. Results show that system savings can be doubled by combining different methods of reducing energy usage of compressed air. This, however, requires continuous monitoring and control of the air network at each section supplied with compressed air. The study is limited to achieving savings by changing the air system. Additional savings can be achieved by training personnel, altering schedules of production activities and implementing a system designed to locate air leaks. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.

Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2008.

Electrical energy is commonly used in households and in industry - demand continues to rise due to economic and population growth. This requires that energy suppliers must increase their supply capacity. The result is that end–user energy costs continue to increase, therefore a growing need exists to reduce electrical energy demand in South Africa and internationally. Households account for the majority of electrical energy customers, but they only consume a fraction of the total energy supplied. The industrial sector and mines combined consume approximately 42% of the total electrical energy produced. Approximately 10% of this energy goes into compressed air production. This study focuses on methods of reducing the requirement of compressed air in industry so that the demand for electrical energy can be reduced. Many studies have focused on specific methods of reducing energy usage associated with compressed air production. These methods are categorised into methods of reducing compressed air requirements and methods of increasing compressed air supply efficiency. This study aims to combine these efforts into a single optimised solution. Although this study includes industry in general, the central focus is on the South African mining industry. Two different mining sites are considered and analysed as case studies. Methods of reducing energy required to produce compressed air were applied to each case study. Case Study 1 only allowed limited control of the compressed air system. In Case Study 2 integrated control was realised. Energy usage of compressors was reduced by 18.9% and 42.9% respectively. Results show that system savings can be doubled by combining different methods of reducing energy usage of compressed air. This, however, requires continuous monitoring and control of the air network at each section supplied with compressed air. The study is limited to achieving savings by changing the air system. Additional savings can be achieved by training personnel, altering schedules of production activities and implementing a system designed to locate air leaks. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2012.

The electricity cost is one of the largest components of operating costs on a belt conveyor system. This dissertation introduces a unique Conveyor Electricity Cost Efficiency Audit Methodology (CECEAM). In the CECEAM the conveyor system is evaluated from a high to detail level in order to identify opportunities to improve electricity costs. The CECEAM includes methodologies and tools developed to analyze not only the conveyor belt alone, but also the materials handling system as a whole. The outline of the dissertation is structured as follows: Chapter 1 includes the background and problem identification by means of a literature study. The main objective, as well as specific objectives, is defined in this chapter. In chapter 2, the CECEAM is introduced and an overview of the total methodology is discussed. The data acquisition part of the CECEAM; documentation, personnel, walk, technical audit as well as the conveyor database is discussed in chapter 3. Chapter 4 concentrates on the Conveyor Energy Conversion Model (CECM) and the verification thereof. The Integrated Conveyor Energy Model (ICEM) methodology is introduced (in chapter 5) and the economic evaluation concepts and energy management basics needed in the CECEAM are covered. Chapter 6 covers a CECEAM case study where the practical application of the CECEAM is illustrated with ICEM simulations, opportunity identification and recommendations. The conclusion and recommendations for further studies is proposed in chapter 7. / Dissertation (MSc (Electrical Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / unrestricted

The innovation of electrical utilities in creating smart electrical grids has superseded that of water utilities in analogous efforts. While many water utilities are now using smart water technologies, they lack the virtual command center that allows for two-way communication for more effective forecasting, load balancing, preventive methods, emergency and master planning, and level of service delivery while ensuring environmental justice and enhancing the responsible use of resources. In this dissertation, I propose the idea of the Integrated Water Distribution System (IWDS) to overcome this challenge. IWDS coordinates management of water supply and demand in a way that benefits both the water utility and the customer. IWDS also allows for greater control over monitoring, operation and maintenance, security, asset management, artificial intelligence, and delivery of water in order to maximize economic, environmental, and social welfare. To provide a way forward for IWDS and bring water services onto a technological level equal to that of other infrastructure systems, I call for greater coordination and integration of smart water technology and data, including environmental justice evaluations, and improved customer engagement. As a demand side management (DSM) tool and smart water technology component of IWDS, smart irrigation controllers (SICs) have the potential to ensure water utilities are resilient to growth and can manage peak day demands. SICs, which interface with soil moisture, evapotranspiration, or weather sensors, have been promoted as a demand-side management tool for this purpose. I review the body of research on residential smart irrigation controllers and their effectiveness. I find that smart irrigation controllers consistently reduce water demand by 15% among general users and more than 40% among indulgent users. A hydraulic model simulation using EPANET demonstrates the effectiveness of residential SICs in shifting and shaving peak demands associated with outdoor irrigation. The pressurized irrigation system for Highland, Utah, USA, is modeled with irrigation demands on a baseline scenario compared to an intervention scenario. By employing the intervention, the water system experiences many positive impacts. Without the peak shifting and shaving adjustments, costly additional capital facility improvements would be needed to maintain the same level of service. The model indicates that the SICs, if providing a 30% conservation effect (intervention scenario with SIC conservation), would shave the peak demand allowing for greater optimization and efficiency. This is the first hydraulic model analysis to demonstrate the DSM effectiveness of SICs.

ESKOM is moving towards a price structure for electricity which reflects, as far as possible, the real cost of generation. It is called real time pricing (RTP). ESKOM developed this cost structure to coax customers to use more electricity in off-peak periods (low cost of generation) and less electricity in peak periods (high cost of generation). However, many industries do not effectively use these price offerings from ESKOM to the detriment of themselves and ESKOM. In previous research improvements to this situation for the South African mining industry were investigated. ESKOM funded research to find the potential for load shifting on mines using RTP. The RTP investigation focused on the supply side management (SSM) in the mining context of underground services on gold and platinum mines. Elements investigated included the ventilation, cooling and pumping (VCP) systems. (Except for pumps, these plants are generally installed aboveground.) Previous research showed a national RTP and SSM potential to shift 500 MW of electrical load for a period of 5 hours. Through the previous research it became clear that the mines were previously able to react partially to the price signals. However, it was proved by the research that the full load shift potential can only be realised through the use of integrated dynamic simulation and optimisation. An even higher potential exists for load shift and electricity efficiency through demand side management (DSM) on the underground services. Therefore, if underground DSM strategies are combined with SSM strategies, a further and much bigger potential can be exploited to the benefit of ESKOM and the mines. Due to these factors this study was undertaken. Three case study mines were identified for this study. They are Kopanang and Target, both gold mines, and Amandelbult, a platinum mine. The DSM potential on each of these mines was calculated using simulation, calibration, verification and optimisation. These results were presented to mine management to negotiate the implementation of the proposed strategies on one of the mines. Kopanang's management agreed to the implementation of these strategies for a trial period of 3 months after which the success would be evaluated. The results of the implementation, together with the case study results, were used to calculate the national DSM potential in the mining sector through extrapolation. The DSM potential amounts to 650 MW of load per day as well as 5% on electricity consumption. This amounts to a potential saving of R72.1 million per year using current tariffs. This means that ESKOM can save about R5000 million on the building of a new power station to supply the equivalent load to the DSM potential. Now that the national impact has been calculated and discussed, all these findings must be used to motivate the implementation of these strategies throughout the mining sector. A similar project can be undertaken to look at possible DSM strategies in the industrial sector. This might prove to be more difficult as the electricity intensive systems are mostly all linked to the final production. In the mind of management this out-weighs the possible cost savings that can be achieved. ESKOM and the NER will have to rethink their strategy. Through DSM and load shifting actions alone the pending electricity crisis will not be averted. The current tariff structures should be amended to not only reflect the true cost of electricity but also provide incentive for DSM and load shifting. Another problem that must be addressed to achieve the DSM targets set for 2007 is the time that it takes to complete the study as well as the implementation time. Software can easily be created to help in the speeding up of the case study itself, as the process and steps followed, as well as models used, are very generic (at least in the gold and platinum mining sector). / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.

ESKOM is moving towards a price structure for electricity which reflects, as far as possible, the real cost of generation. It is called real time pricing (RTP). ESKOM developed this cost structure to coax customers to use more electricity in off-peak periods (low cost of generation) and less electricity in peak periods (high cost of generation). However, many industries do not effectively use these price offerings from ESKOM to the detriment of themselves and ESKOM. In previous research improvements to this situation for the South African mining industry were investigated. ESKOM funded research to find the potential for load shifting on mines using RTP. The RTP investigation focused on the supply side management (SSM) in the mining context of underground services on gold and platinum mines. Elements investigated included the ventilation, cooling and pumping (VCP) systems. (Except for pumps, these plants are generally installed aboveground.) Previous research showed a national RTP and SSM potential to shift 500 MW of electrical load for a period of 5 hours. Through the previous research it became clear that the mines were previously able to react partially to the price signals. However, it was proved by the research that the full load shift potential can only be realised through the use of integrated dynamic simulation and optimisation. An even higher potential exists for load shift and electricity efficiency through demand side management (DSM) on the underground services. Therefore, if underground DSM strategies are combined with SSM strategies, a further and much bigger potential can be exploited to the benefit of ESKOM and the mines. Due to these factors this study was undertaken. Three case study mines were identified for this study. They are Kopanang and Target, both gold mines, and Amandelbult, a platinum mine. The DSM potential on each of these mines was calculated using simulation, calibration, verification and optimisation. These results were presented to mine management to negotiate the implementation of the proposed strategies on one of the mines. Kopanang's management agreed to the implementation of these strategies for a trial period of 3 months after which the success would be evaluated. The results of the implementation, together with the case study results, were used to calculate the national DSM potential in the mining sector through extrapolation. The DSM potential amounts to 650 MW of load per day as well as 5% on electricity consumption. This amounts to a potential saving of R72.1 million per year using current tariffs. This means that ESKOM can save about R5000 million on the building of a new power station to supply the equivalent load to the DSM potential. Now that the national impact has been calculated and discussed, all these findings must be used to motivate the implementation of these strategies throughout the mining sector. A similar project can be undertaken to look at possible DSM strategies in the industrial sector. This might prove to be more difficult as the electricity intensive systems are mostly all linked to the final production. In the mind of management this out-weighs the possible cost savings that can be achieved. ESKOM and the NER will have to rethink their strategy. Through DSM and load shifting actions alone the pending electricity crisis will not be averted. The current tariff structures should be amended to not only reflect the true cost of electricity but also provide incentive for DSM and load shifting. Another problem that must be addressed to achieve the DSM targets set for 2007 is the time that it takes to complete the study as well as the implementation time. Software can easily be created to help in the speeding up of the case study itself, as the process and steps followed, as well as models used, are very generic (at least in the gold and platinum mining sector). / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.

La thèse répond à deux problématiques, d'une part la quantification des effacements de consommation d'électricité par technologies gaz dans l'habitat et d'autre part de l'intégration de leurs valorisations dans une perspective de planification des infrastructures. Ces travaux se justifient dans un contexte d'augmentation de la pointe électrique, à l'origine d'une hausse du risque de défaillance du système, et de la baisse des consommations de gaz naturel conduisant à une sous utilisation du réseau de distribution. Pourtant, alors que la demande en gaz naturel croît du fait de l'installation de centrales à cycle combiné sur le réseau de transport, l'interaction des réseaux de distribution gaz/électricité n'est pas exploitée.Ce manuscrit envisage l'intégration des technologies gaz comme moyen de Maîtrise de la Demande en Électricité dans le processus de planification des réseaux. Ainsi les effacements de consommations d'électricité lors des périodes dimensionnantes par des micro-cogénérateurs ou des chaudières hybrides sont des solutions alternatives aux solutions de renforcement de réseaux.Pour quantifier le gisement d'effacement, nous nous intéressons à l'impact marginal des systèmes sur la demande en termes de modification de la quantité d'Énergie Non Distribuée potentielle. Les estimations des impacts de systèmes de chauffage sur la demande sont donc des prérequis à cette approche. Nous modélisons les courbes de charge régionales par une approche Bottom-Up permettant de déterminer les profils de demande marginale de chauffage en fonction des systèmes. La mise en application de cette méthode est à fiabiliser par des études socio-technico-économiques permettant de réduire les incertitudes sur les déterminants des besoins de chauffage. Une calibration en puissance des profils générés a été proposée mais n'a pu être réalisée. En revanche, nous apportons une contribution à l'analyse des courbes de charge agrégées en montrant que le modèle d'estimation actuellement utilisé par le gestionnaire de réseau s'apparente à un modèle simplifié de bâtiment / This PhD thesis addresses two issues: Firstly, the assessment of Demand Side Management (DSM) opportunity of gas and electricity technologies in dwellings, and secondly, the integration of their valuations in infrastructure planning schemes.This work originaites from a context of the growth of electricity peaks (which increased risk of system failure) and the natural gas consumption decrease which leads to an under-utilization of the gas distribution network.This manuscript focuses on the integration of gas technologies as DSM solution to contribute to the planning of electricity grid. Indeed, relieving the electricity consumption during constrained periods by diffusing micro-cogeneration or hybrid boiler, is an actual alternative to network reinforcement solutions. To quantify the load shedding capacity, we are interested in the marginal impact of demand systems on the amount of Energy Not Supplied potential. Estimating systems' impacts on heating demand is a prerequisite to this approach. So we model the regional heating load curves by a Bottom-Up approach to simulate marginal demand profiles depending on heating systems. The implementation of this method requires socio-technico-economic studies to reduce uncertainty of the determinants of heating needs. A load calibration methodology has been proposed but has not been performed. However, we make a contribution to the analysis of aggregated load curves emphasizing that the load model currently used by network operator similar to a simplified building model.